diff --git a/dendrite-sample.polylith.yaml b/dendrite-sample.polylith.yaml
index 83dbba0bf..78a1b3b92 100644
--- a/dendrite-sample.polylith.yaml
+++ b/dendrite-sample.polylith.yaml
@@ -125,7 +125,7 @@ app_service_api:
 
   # Database configuration for this component.
   database:
-    connection_string: postgresql://username@password:hostname/dendrite_appservice?sslmode=disable
+    connection_string: postgresql://username:password@hostname/dendrite_appservice?sslmode=disable
     max_open_conns: 10
     max_idle_conns: 2
     conn_max_lifetime: -1
@@ -209,7 +209,7 @@ federation_api:
   external_api:
     listen: http://[::]:8072
   database:
-    connection_string: postgresql://username@password:hostname/dendrite_federationapi?sslmode=disable
+    connection_string: postgresql://username:password@hostname/dendrite_federationapi?sslmode=disable
     max_open_conns: 10
     max_idle_conns: 2
     conn_max_lifetime: -1
@@ -246,7 +246,7 @@ key_server:
     listen: http://[::]:7779 # The listen address for incoming API requests
     connect: http://key_server:7779 # The connect address for other components to use
   database:
-    connection_string: postgresql://username@password:hostname/dendrite_keyserver?sslmode=disable
+    connection_string: postgresql://username:password@hostname/dendrite_keyserver?sslmode=disable
     max_open_conns: 10
     max_idle_conns: 2
     conn_max_lifetime: -1
@@ -259,7 +259,7 @@ media_api:
   external_api:
     listen: http://[::]:8074
   database:
-    connection_string: postgresql://username@password:hostname/dendrite_mediaapi?sslmode=disable
+    connection_string: postgresql://username:password@hostname/dendrite_mediaapi?sslmode=disable
     max_open_conns: 5
     max_idle_conns: 2
     conn_max_lifetime: -1
@@ -296,7 +296,7 @@ mscs:
   #  - msc2836  # (Threading, see https://github.com/matrix-org/matrix-doc/pull/2836)
   #  - msc2946  # (Spaces Summary, see https://github.com/matrix-org/matrix-doc/pull/2946)
   database:
-    connection_string: postgresql://username@password:hostname/dendrite_mscs?sslmode=disable
+    connection_string: postgresql://username:password@hostname/dendrite_mscs?sslmode=disable
     max_open_conns: 5
     max_idle_conns: 2
     conn_max_lifetime: -1
@@ -307,7 +307,7 @@ room_server:
     listen: http://[::]:7770 # The listen address for incoming API requests
     connect: http://room_server:7770 # The connect address for other components to use
   database:
-    connection_string: postgresql://username@password:hostname/dendrite_roomserver?sslmode=disable
+    connection_string: postgresql://username:password@hostname/dendrite_roomserver?sslmode=disable
     max_open_conns: 10
     max_idle_conns: 2
     conn_max_lifetime: -1
@@ -320,7 +320,7 @@ sync_api:
   external_api:
     listen: http://[::]:8073
   database:
-    connection_string: postgresql://username@password:hostname/dendrite_syncapi?sslmode=disable
+    connection_string: postgresql://username:password@hostname/dendrite_syncapi?sslmode=disable
     max_open_conns: 10
     max_idle_conns: 2
     conn_max_lifetime: -1
@@ -336,7 +336,7 @@ user_api:
     listen: http://[::]:7781 # The listen address for incoming API requests
     connect: http://user_api:7781 # The connect address for other components to use
   account_database:
-    connection_string: postgresql://username@password:hostname/dendrite_userapi?sslmode=disable
+    connection_string: postgresql://username:password@hostname/dendrite_userapi?sslmode=disable
     max_open_conns: 10
     max_idle_conns: 2
     conn_max_lifetime: -1
diff --git a/docs/FAQ.md b/docs/FAQ.md
index 47f39b9e6..f8255684e 100644
--- a/docs/FAQ.md
+++ b/docs/FAQ.md
@@ -86,9 +86,12 @@ would be a huge help too, as that will help us to understand where the memory us
 
 You may need to revisit the connection limit of your PostgreSQL server and/or make changes to the `max_connections` lines in your Dendrite configuration. Be aware that each Dendrite component opens its own database connections and has its own connection limit, even in monolith mode!
 
-## What is being reported when enabling anonymous stats?
+## What is being reported when enabling phone-home statistics?
 
-If anonymous stats reporting is enabled, the following data is send to the defined endpoint.
+Phone-home statistics contain your server's domain name, some configuration information about
+your deployment and aggregated information about active users on your deployment. They are sent
+to the endpoint URL configured in your Dendrite configuration file only. The following is an
+example of the data that is sent:
 
 ```json
 {
@@ -106,7 +109,7 @@ If anonymous stats reporting is enabled, the following data is send to the defin
     "go_arch": "amd64",
     "go_os": "linux",
     "go_version": "go1.16.13",
-    "homeserver": "localhost:8800",
+    "homeserver": "my.domain.com",
     "log_level": "trace",
     "memory_rss": 93452,
     "monolith": true,
diff --git a/docs/administration/1_createusers.md b/docs/administration/1_createusers.md
index f40b7f576..61ec2299b 100644
--- a/docs/administration/1_createusers.md
+++ b/docs/administration/1_createusers.md
@@ -32,6 +32,15 @@ To create a new **admin account**, add the `-admin` flag:
 ./bin/create-account -config /path/to/dendrite.yaml -username USERNAME -admin
 ```
 
+An example of using `create-account` when running in **Docker**, having found the `CONTAINERNAME` from `docker ps`:
+
+```bash
+docker exec -it CONTAINERNAME /usr/bin/create-account -config /path/to/dendrite.yaml -username USERNAME
+```
+```bash
+docker exec -it CONTAINERNAME /usr/bin/create-account -config /path/to/dendrite.yaml -username USERNAME -admin
+```
+
 ## Using shared secret registration
 
 Dendrite supports the Synapse-compatible shared secret registration endpoint.
diff --git a/docs/installation/2_domainname.md b/docs/installation/2_domainname.md
index 0d4300eca..54064acb4 100644
--- a/docs/installation/2_domainname.md
+++ b/docs/installation/2_domainname.md
@@ -14,15 +14,18 @@ that take the format `@user:example.com`.
 For federation to work, the server name must be resolvable by other homeservers on the internet
 — that is, the domain must be registered and properly configured with the relevant DNS records.
 
-Matrix servers discover each other when federating using the following methods:
+Matrix servers usually discover each other when federating using the following methods:
 
-1. If a well-known delegation exists on `example.com`, use the path server from the
+1. If a well-known delegation exists on `example.com`, use the domain and port from the
    well-known file to connect to the remote homeserver;
-2. If a DNS SRV delegation exists on `example.com`, use the hostname and port from the DNS SRV
+2. If a DNS SRV delegation exists on `example.com`, use the IP address and port from the DNS SRV
    record to connect to the remote homeserver;
 3. If neither well-known or DNS SRV delegation are configured, attempt to connect to the remote
    homeserver by connecting to `example.com` port TCP/8448 using HTTPS.
 
+The exact details of how server name resolution works can be found in
+[the spec](https://spec.matrix.org/v1.3/server-server-api/#resolving-server-names).
+
 ## TLS certificates
 
 Matrix federation requires that valid TLS certificates are present on the domain. You must
@@ -51,17 +54,12 @@ you will be able to delegate from `example.com` to `matrix.example.com` so that
 
 Delegation can be performed in one of two ways:
 
-* **Well-known delegation**: A well-known text file is served over HTTPS on the domain name
-  that you want to use, pointing to your server on `matrix.example.com` port 8448;
-* **DNS SRV delegation**: A DNS SRV record is created on the domain name that you want to
-  use, pointing to your server on `matrix.example.com` port TCP/8448.
+* **Well-known delegation (preferred)**: A well-known text file is served over HTTPS on the domain
+  name that you want to use, pointing to your server on `matrix.example.com` port 8448;
+* **DNS SRV delegation (not recommended)**: See the SRV delegation section below for details.
 
-If you are using a reverse proxy to forward `/_matrix` to Dendrite, your well-known or DNS SRV
-delegation must refer to the hostname and port that the reverse proxy is listening on instead.
-
-Well-known delegation is typically easier to set up and usually preferred. However, you can use
-either or both methods to delegate. If you configure both methods of delegation, it is important
-that they both agree and refer to the same hostname and port.
+If you are using a reverse proxy to forward `/_matrix` to Dendrite, your well-known or delegation
+must refer to the hostname and port that the reverse proxy is listening on instead.
 
 ## Well-known delegation
 
@@ -74,20 +72,36 @@ and contain the following JSON document:
 
 ```json
 {
-    "m.server": "https://matrix.example.com:8448"
+    "m.server": "matrix.example.com:8448"
 }
 ```
 
+You can also serve `.well-known` with Dendrite itself by setting the `well_known_server_name` config
+option to the value you want for `m.server`. This is primarily useful if Dendrite is exposed on
+`example.com:443` and you don't want to set up a separate webserver just for serving the `.well-known`
+file.
+
+```yaml
+global:
+...
+   well_known_server_name: "example.com:443"
+```
+
 ## DNS SRV delegation
 
-Using DNS SRV delegation requires creating DNS SRV records on the `example.com` zone which
-refer to your Dendrite installation.
+This method is not recommended, as the behavior of SRV records in Matrix is rather unintuitive:
+SRV records will only change the IP address and port that other servers connect to, they won't
+affect the domain name. In technical terms, the `Host` header and TLS SNI of federation requests
+will still be `example.com` even if the SRV record points at `matrix.example.com`.
 
-Assuming that your Dendrite installation is listening for HTTPS connections at `matrix.example.com`
-port 8448, the DNS SRV record must have the following fields:
+In practice, this means that the server must be configured with valid TLS certificates for
+`example.com`, rather than `matrix.example.com` as one might intuitively expect. If there's a
+reverse proxy in between, the proxy configuration must be written as if it's `example.com`, as the
+proxy will never see the name `matrix.example.com` in incoming requests.
 
-* Name: `@` (or whichever term your DNS provider uses to signal the root)
-* Service: `_matrix`
-* Protocol: `_tcp`
-* Port: `8448`
-* Target: `matrix.example.com`
+This behavior also means that if `example.com` and `matrix.example.com` point at the same IP
+address, there is no reason to have a SRV record pointing at `matrix.example.com`. It can still
+be used to change the port number, but it won't do anything else.
+
+If you understand how SRV records work and still want to use them, the service name is `_matrix` and
+the protocol is `_tcp`.
diff --git a/go.mod b/go.mod
index c9170a861..7c6345684 100644
--- a/go.mod
+++ b/go.mod
@@ -25,7 +25,7 @@ require (
 	github.com/matrix-org/dugong v0.0.0-20210921133753-66e6b1c67e2e
 	github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91
 	github.com/matrix-org/gomatrix v0.0.0-20210324163249-be2af5ef2e16
-	github.com/matrix-org/gomatrixserverlib v0.0.0-20220713083127-fc2ea1e62e46
+	github.com/matrix-org/gomatrixserverlib v0.0.0-20220718085240-f08f98af7d2d
 	github.com/matrix-org/pinecone v0.0.0-20220708135211-1ce778fcde6a
 	github.com/matrix-org/util v0.0.0-20200807132607-55161520e1d4
 	github.com/mattn/go-sqlite3 v1.14.13
diff --git a/go.sum b/go.sum
index d86c8cb46..d9ba933d9 100644
--- a/go.sum
+++ b/go.sum
@@ -476,8 +476,8 @@ github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91/go.mod h1
 github.com/matrix-org/gomatrix v0.0.0-20190528120928-7df988a63f26/go.mod h1:3fxX6gUjWyI/2Bt7J1OLhpCzOfO/bB3AiX0cJtEKud0=
 github.com/matrix-org/gomatrix v0.0.0-20210324163249-be2af5ef2e16 h1:ZtO5uywdd5dLDCud4r0r55eP4j9FuUNpl60Gmntcop4=
 github.com/matrix-org/gomatrix v0.0.0-20210324163249-be2af5ef2e16/go.mod h1:/gBX06Kw0exX1HrwmoBibFA98yBk/jxKpGVeyQbff+s=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20220713083127-fc2ea1e62e46 h1:5X/kXY3nwqKOwwrE9tnMKrjbsi3PHigQYvrvDBSntO8=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20220713083127-fc2ea1e62e46/go.mod h1:jX38yp3SSLJNftBg3PXU1ayd0PCLIiDHQ4xAc9DIixk=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20220718085240-f08f98af7d2d h1:BWInUURXVOW+OiifMapoRIS7i122KWdEKj6fnDFXgBo=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20220718085240-f08f98af7d2d/go.mod h1:jX38yp3SSLJNftBg3PXU1ayd0PCLIiDHQ4xAc9DIixk=
 github.com/matrix-org/pinecone v0.0.0-20220708135211-1ce778fcde6a h1:DdG8vXMlZ65EAtc4V+3t7zHZ2Gqs24pSnyXS+4BRHUs=
 github.com/matrix-org/pinecone v0.0.0-20220708135211-1ce778fcde6a/go.mod h1:ulJzsVOTssIVp1j/m5eI//4VpAGDkMt5NrRuAVX7wpc=
 github.com/matrix-org/util v0.0.0-20190711121626-527ce5ddefc7/go.mod h1:vVQlW/emklohkZnOPwD3LrZUBqdfsbiyO3p1lNV8F6U=
diff --git a/internal/caching/cache_eventstatekeys.go b/internal/caching/cache_eventstatekeys.go
new file mode 100644
index 000000000..05580ab05
--- /dev/null
+++ b/internal/caching/cache_eventstatekeys.go
@@ -0,0 +1,18 @@
+package caching
+
+import "github.com/matrix-org/dendrite/roomserver/types"
+
+// EventStateKeyCache contains the subset of functions needed for
+// a room event state key cache.
+type EventStateKeyCache interface {
+	GetEventStateKey(eventStateKeyNID types.EventStateKeyNID) (string, bool)
+	StoreEventStateKey(eventStateKeyNID types.EventStateKeyNID, eventStateKey string)
+}
+
+func (c Caches) GetEventStateKey(eventStateKeyNID types.EventStateKeyNID) (string, bool) {
+	return c.RoomServerStateKeys.Get(eventStateKeyNID)
+}
+
+func (c Caches) StoreEventStateKey(eventStateKeyNID types.EventStateKeyNID, eventStateKey string) {
+	c.RoomServerStateKeys.Set(eventStateKeyNID, eventStateKey)
+}
diff --git a/internal/caching/cache_roomservernids.go b/internal/caching/cache_roomservernids.go
index b409aeef2..f27154f19 100644
--- a/internal/caching/cache_roomservernids.go
+++ b/internal/caching/cache_roomservernids.go
@@ -9,6 +9,7 @@ type RoomServerCaches interface {
 	RoomVersionCache
 	RoomInfoCache
 	RoomServerEventsCache
+	EventStateKeyCache
 }
 
 // RoomServerNIDsCache contains the subset of functions needed for
@@ -19,9 +20,9 @@ type RoomServerNIDsCache interface {
 }
 
 func (c Caches) GetRoomServerRoomID(roomNID types.RoomNID) (string, bool) {
-	return c.RoomServerRoomIDs.Get(int64(roomNID))
+	return c.RoomServerRoomIDs.Get(roomNID)
 }
 
 func (c Caches) StoreRoomServerRoomID(roomNID types.RoomNID, roomID string) {
-	c.RoomServerRoomIDs.Set(int64(roomNID), roomID)
+	c.RoomServerRoomIDs.Set(roomNID, roomID)
 }
diff --git a/internal/caching/caches.go b/internal/caching/caches.go
index e7914ce7d..f13f743d3 100644
--- a/internal/caching/caches.go
+++ b/internal/caching/caches.go
@@ -23,16 +23,17 @@ import (
 // different implementations as long as they satisfy the Cache
 // interface.
 type Caches struct {
-	RoomVersions       Cache[string, gomatrixserverlib.RoomVersion]           // room ID -> room version
-	ServerKeys         Cache[string, gomatrixserverlib.PublicKeyLookupResult] // server name -> server keys
-	RoomServerRoomNIDs Cache[string, types.RoomNID]                           // room ID -> room NID
-	RoomServerRoomIDs  Cache[int64, string]                                   // room NID -> room ID
-	RoomServerEvents   Cache[int64, *gomatrixserverlib.Event]                 // event NID -> event
-	RoomInfos          Cache[string, *types.RoomInfo]                         // room ID -> room info
-	FederationPDUs     Cache[int64, *gomatrixserverlib.HeaderedEvent]         // queue NID -> PDU
-	FederationEDUs     Cache[int64, *gomatrixserverlib.EDU]                   // queue NID -> EDU
-	SpaceSummaryRooms  Cache[string, gomatrixserverlib.MSC2946SpacesResponse] // room ID -> space response
-	LazyLoading        Cache[lazyLoadingCacheKey, string]                     // composite key -> event ID
+	RoomVersions        Cache[string, gomatrixserverlib.RoomVersion]           // room ID -> room version
+	ServerKeys          Cache[string, gomatrixserverlib.PublicKeyLookupResult] // server name -> server keys
+	RoomServerRoomNIDs  Cache[string, types.RoomNID]                           // room ID -> room NID
+	RoomServerRoomIDs   Cache[types.RoomNID, string]                           // room NID -> room ID
+	RoomServerEvents    Cache[int64, *gomatrixserverlib.Event]                 // event NID -> event
+	RoomServerStateKeys Cache[types.EventStateKeyNID, string]                  // event NID -> event state key
+	RoomInfos           Cache[string, *types.RoomInfo]                         // room ID -> room info
+	FederationPDUs      Cache[int64, *gomatrixserverlib.HeaderedEvent]         // queue NID -> PDU
+	FederationEDUs      Cache[int64, *gomatrixserverlib.EDU]                   // queue NID -> EDU
+	SpaceSummaryRooms   Cache[string, gomatrixserverlib.MSC2946SpacesResponse] // room ID -> space response
+	LazyLoading         Cache[lazyLoadingCacheKey, string]                     // composite key -> event ID
 }
 
 // Cache is the interface that an implementation must satisfy.
@@ -44,7 +45,7 @@ type Cache[K keyable, T any] interface {
 
 type keyable interface {
 	// from https://github.com/dgraph-io/ristretto/blob/8e850b710d6df0383c375ec6a7beae4ce48fc8d5/z/z.go#L34
-	uint64 | string | []byte | byte | int | int32 | uint32 | int64 | lazyLoadingCacheKey
+	~uint64 | ~string | []byte | byte | ~int | ~int32 | ~uint32 | ~int64 | lazyLoadingCacheKey
 }
 
 type costable interface {
diff --git a/internal/caching/impl_ristretto.go b/internal/caching/impl_ristretto.go
index 677218b5e..fdbbb4d72 100644
--- a/internal/caching/impl_ristretto.go
+++ b/internal/caching/impl_ristretto.go
@@ -40,13 +40,14 @@ const (
 	federationEDUsCache
 	spaceSummaryRoomsCache
 	lazyLoadingCache
+	eventStateKeyCache
 )
 
 func NewRistrettoCache(maxCost config.DataUnit, maxAge time.Duration, enablePrometheus bool) *Caches {
 	cache, err := ristretto.NewCache(&ristretto.Config{
-		NumCounters: 1e5, // 10x number of expected cache items, affects bloom filter size, gives us room for 10,000 currently
-		BufferItems: 64,  // recommended by the ristretto godocs as a sane buffer size value
-		MaxCost:     int64(maxCost),
+		NumCounters: int64((maxCost / 1024) * 10), // 10 counters per 1KB data, affects bloom filter size
+		BufferItems: 64,                           // recommended by the ristretto godocs as a sane buffer size value
+		MaxCost:     int64(maxCost),               // max cost is in bytes, as per the Dendrite config
 		Metrics:     true,
 		KeyToHash: func(key interface{}) (uint64, uint64) {
 			return z.KeyToHash(key)
@@ -88,7 +89,7 @@ func NewRistrettoCache(maxCost config.DataUnit, maxAge time.Duration, enableProm
 			Prefix: roomNIDsCache,
 			MaxAge: maxAge,
 		},
-		RoomServerRoomIDs: &RistrettoCachePartition[int64, string]{ // room NID -> room ID
+		RoomServerRoomIDs: &RistrettoCachePartition[types.RoomNID, string]{ // room NID -> room ID
 			cache:  cache,
 			Prefix: roomIDsCache,
 			MaxAge: maxAge,
@@ -100,6 +101,11 @@ func NewRistrettoCache(maxCost config.DataUnit, maxAge time.Duration, enableProm
 				MaxAge: maxAge,
 			},
 		},
+		RoomServerStateKeys: &RistrettoCachePartition[types.EventStateKeyNID, string]{ // event NID -> event state key
+			cache:  cache,
+			Prefix: eventStateKeyCache,
+			MaxAge: maxAge,
+		},
 		RoomInfos: &RistrettoCachePartition[string, *types.RoomInfo]{ // room ID -> room info
 			cache:   cache,
 			Prefix:  roomInfosCache,
diff --git a/roomserver/storage/shared/membership_updater.go b/roomserver/storage/shared/membership_updater.go
index ebfcef569..c79ca8995 100644
--- a/roomserver/storage/shared/membership_updater.go
+++ b/roomserver/storage/shared/membership_updater.go
@@ -105,8 +105,15 @@ func (u *MembershipUpdater) SetToInvite(event *gomatrixserverlib.Event) (bool, e
 		if err != nil {
 			return fmt.Errorf("u.d.InvitesTable.InsertInviteEvent: %w", err)
 		}
+
+		// Look up the NID of the invite event
+		nIDs, err := u.d.eventNIDs(u.ctx, u.txn, []string{event.EventID()}, false)
+		if err != nil {
+			return fmt.Errorf("u.d.EventNIDs: %w", err)
+		}
+
 		if u.membership != tables.MembershipStateInvite {
-			if inserted, err = u.d.MembershipTable.UpdateMembership(u.ctx, u.txn, u.roomNID, u.targetUserNID, senderUserNID, tables.MembershipStateInvite, 0, false); err != nil {
+			if inserted, err = u.d.MembershipTable.UpdateMembership(u.ctx, u.txn, u.roomNID, u.targetUserNID, senderUserNID, tables.MembershipStateInvite, nIDs[event.EventID()], false); err != nil {
 				return fmt.Errorf("u.d.MembershipTable.UpdateMembership: %w", err)
 			}
 		}
diff --git a/roomserver/storage/shared/storage.go b/roomserver/storage/shared/storage.go
index d8d5f67c8..2f9932ff8 100644
--- a/roomserver/storage/shared/storage.go
+++ b/roomserver/storage/shared/storage.go
@@ -72,7 +72,24 @@ func (d *Database) eventTypeNIDs(
 func (d *Database) EventStateKeys(
 	ctx context.Context, eventStateKeyNIDs []types.EventStateKeyNID,
 ) (map[types.EventStateKeyNID]string, error) {
-	return d.EventStateKeysTable.BulkSelectEventStateKey(ctx, nil, eventStateKeyNIDs)
+	result := make(map[types.EventStateKeyNID]string, len(eventStateKeyNIDs))
+	fetch := make([]types.EventStateKeyNID, 0, len(eventStateKeyNIDs))
+	for _, nid := range eventStateKeyNIDs {
+		if key, ok := d.Cache.GetEventStateKey(nid); ok {
+			result[nid] = key
+		} else {
+			fetch = append(fetch, nid)
+		}
+	}
+	fromDB, err := d.EventStateKeysTable.BulkSelectEventStateKey(ctx, nil, fetch)
+	if err != nil {
+		return nil, err
+	}
+	for nid, key := range fromDB {
+		result[nid] = key
+		d.Cache.StoreEventStateKey(nid, key)
+	}
+	return result, nil
 }
 
 func (d *Database) EventStateKeyNIDs(
diff --git a/setup/config/config_global.go b/setup/config/config_global.go
index ac1380a4e..10827bb21 100644
--- a/setup/config/config_global.go
+++ b/setup/config/config_global.go
@@ -73,7 +73,7 @@ type Global struct {
 	// ServerNotices configuration used for sending server notices
 	ServerNotices ServerNotices `yaml:"server_notices"`
 
-	// ReportStats configures opt-in anonymous stats reporting.
+	// ReportStats configures opt-in phone-home statistics reporting.
 	ReportStats ReportStats `yaml:"report_stats"`
 
 	// Configuration for the caches.
@@ -189,9 +189,9 @@ func (c *Cache) Verify(errors *ConfigErrors, isMonolith bool) {
 	checkPositive(errors, "max_size_estimated", int64(c.EstimatedMaxSize))
 }
 
-// ReportStats configures opt-in anonymous stats reporting.
+// ReportStats configures opt-in phone-home statistics reporting.
 type ReportStats struct {
-	// Enabled configures anonymous usage stats of the server
+	// Enabled configures phone-home statistics of the server
 	Enabled bool `yaml:"enabled"`
 
 	// Endpoint the endpoint to report stats to
diff --git a/syncapi/consumers/roomserver.go b/syncapi/consumers/roomserver.go
index f0ca2106f..328e1e9dd 100644
--- a/syncapi/consumers/roomserver.go
+++ b/syncapi/consumers/roomserver.go
@@ -240,6 +240,7 @@ func (s *OutputRoomEventConsumer) onNewRoomEvent(
 		msg.RemovesStateEventIDs,
 		msg.TransactionID,
 		false,
+		msg.HistoryVisibility,
 	)
 	if err != nil {
 		// panic rather than continue with an inconsistent database
@@ -289,7 +290,8 @@ func (s *OutputRoomEventConsumer) onOldRoomEvent(
 		[]string{},           // adds no state
 		[]string{},           // removes no state
 		nil,                  // no transaction
-		ev.StateKey() != nil, // exclude from sync?
+		ev.StateKey() != nil, // exclude from sync?,
+		msg.HistoryVisibility,
 	)
 	if err != nil {
 		// panic rather than continue with an inconsistent database
diff --git a/syncapi/internal/keychange.go b/syncapi/internal/keychange.go
index d96718d20..03df9285c 100644
--- a/syncapi/internal/keychange.go
+++ b/syncapi/internal/keychange.go
@@ -21,6 +21,7 @@ import (
 	keyapi "github.com/matrix-org/dendrite/keyserver/api"
 	keytypes "github.com/matrix-org/dendrite/keyserver/types"
 	roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/syncapi/storage"
 	"github.com/matrix-org/dendrite/syncapi/types"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
@@ -46,7 +47,7 @@ func DeviceOTKCounts(ctx context.Context, keyAPI keyapi.SyncKeyAPI, userID, devi
 // was filled in, else false if there are no new device list changes because there is nothing to catch up on. The response MUST
 // be already filled in with join/leave information.
 func DeviceListCatchup(
-	ctx context.Context, keyAPI keyapi.SyncKeyAPI, rsAPI roomserverAPI.SyncRoomserverAPI,
+	ctx context.Context, db storage.SharedUsers, keyAPI keyapi.SyncKeyAPI, rsAPI roomserverAPI.SyncRoomserverAPI,
 	userID string, res *types.Response, from, to types.StreamPosition,
 ) (newPos types.StreamPosition, hasNew bool, err error) {
 
@@ -93,7 +94,7 @@ func DeviceListCatchup(
 	queryRes.UserIDs = append(queryRes.UserIDs, leaveUserIDs...)
 	queryRes.UserIDs = util.UniqueStrings(queryRes.UserIDs)
 	var sharedUsersMap map[string]int
-	sharedUsersMap, queryRes.UserIDs = filterSharedUsers(ctx, rsAPI, userID, queryRes.UserIDs)
+	sharedUsersMap, queryRes.UserIDs = filterSharedUsers(ctx, db, userID, queryRes.UserIDs)
 	util.GetLogger(ctx).Debugf(
 		"QueryKeyChanges request off=%d,to=%d response off=%d uids=%v",
 		offset, toOffset, queryRes.Offset, queryRes.UserIDs,
@@ -215,30 +216,28 @@ func TrackChangedUsers(
 	return changed, left, nil
 }
 
+// filterSharedUsers takes a list of remote users whose keys have changed and filters
+// it down to include only users who the requesting user shares a room with.
 func filterSharedUsers(
-	ctx context.Context, rsAPI roomserverAPI.SyncRoomserverAPI, userID string, usersWithChangedKeys []string,
+	ctx context.Context, db storage.SharedUsers, userID string, usersWithChangedKeys []string,
 ) (map[string]int, []string) {
-	var result []string
-	var sharedUsersRes roomserverAPI.QuerySharedUsersResponse
-	err := rsAPI.QuerySharedUsers(ctx, &roomserverAPI.QuerySharedUsersRequest{
-		UserID:       userID,
-		OtherUserIDs: usersWithChangedKeys,
-	}, &sharedUsersRes)
+	sharedUsersMap := make(map[string]int, len(usersWithChangedKeys))
+	for _, userID := range usersWithChangedKeys {
+		sharedUsersMap[userID] = 0
+	}
+	sharedUsers, err := db.SharedUsers(ctx, userID, usersWithChangedKeys)
 	if err != nil {
 		// default to all users so we do needless queries rather than miss some important device update
 		return nil, usersWithChangedKeys
 	}
+	for _, userID := range sharedUsers {
+		sharedUsersMap[userID]++
+	}
 	// We forcibly put ourselves in this list because we should be notified about our own device updates
 	// and if we are in 0 rooms then we don't technically share any room with ourselves so we wouldn't
 	// be notified about key changes.
-	sharedUsersRes.UserIDsToCount[userID] = 1
-
-	for _, uid := range usersWithChangedKeys {
-		if sharedUsersRes.UserIDsToCount[uid] > 0 {
-			result = append(result, uid)
-		}
-	}
-	return sharedUsersRes.UserIDsToCount, result
+	sharedUsersMap[userID] = 1
+	return sharedUsersMap, sharedUsers
 }
 
 func joinedRooms(res *types.Response, userID string) []string {
diff --git a/syncapi/internal/keychange_test.go b/syncapi/internal/keychange_test.go
index 219b35e2c..79ed440e7 100644
--- a/syncapi/internal/keychange_test.go
+++ b/syncapi/internal/keychange_test.go
@@ -11,6 +11,7 @@ import (
 	"github.com/matrix-org/dendrite/syncapi/types"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
 )
 
 var (
@@ -105,6 +106,22 @@ func (s *mockRoomserverAPI) QuerySharedUsers(ctx context.Context, req *api.Query
 	return nil
 }
 
+// This is actually a database function, but seeing as we track the state inside the
+// *mockRoomserverAPI, we'll just comply with the interface here instead.
+func (s *mockRoomserverAPI) SharedUsers(ctx context.Context, userID string, otherUserIDs []string) ([]string, error) {
+	commonUsers := []string{}
+	for _, members := range s.roomIDToJoinedMembers {
+		for _, member := range members {
+			for _, userID := range otherUserIDs {
+				if member == userID {
+					commonUsers = append(commonUsers, userID)
+				}
+			}
+		}
+	}
+	return util.UniqueStrings(commonUsers), nil
+}
+
 type wantCatchup struct {
 	hasNew  bool
 	changed []string
@@ -178,7 +195,7 @@ func TestKeyChangeCatchupOnJoinShareNewUser(t *testing.T) {
 			"!another:room": {syncingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), rsAPI, &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
 	}
@@ -201,7 +218,7 @@ func TestKeyChangeCatchupOnLeaveShareLeftUser(t *testing.T) {
 			"!another:room": {syncingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), rsAPI, &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
 	}
@@ -224,7 +241,7 @@ func TestKeyChangeCatchupOnJoinShareNoNewUsers(t *testing.T) {
 			"!another:room": {syncingUser, existingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), rsAPI, &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("Catchup returned an error: %s", err)
 	}
@@ -246,7 +263,7 @@ func TestKeyChangeCatchupOnLeaveShareNoUsers(t *testing.T) {
 			"!another:room": {syncingUser, existingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), rsAPI, &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
 	}
@@ -305,7 +322,7 @@ func TestKeyChangeCatchupNoNewJoinsButMessages(t *testing.T) {
 			roomID: {syncingUser, existingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), rsAPI, &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
 	}
@@ -333,7 +350,7 @@ func TestKeyChangeCatchupChangeAndLeft(t *testing.T) {
 			"!another:room": {syncingUser},
 		},
 	}
-	_, hasNew, err := DeviceListCatchup(context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
+	_, hasNew, err := DeviceListCatchup(context.Background(), rsAPI, &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken)
 	if err != nil {
 		t.Fatalf("Catchup returned an error: %s", err)
 	}
@@ -419,7 +436,7 @@ func TestKeyChangeCatchupChangeAndLeftSameRoom(t *testing.T) {
 		},
 	}
 	_, hasNew, err := DeviceListCatchup(
-		context.Background(), &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken,
+		context.Background(), rsAPI, &mockKeyAPI{}, rsAPI, syncingUser, syncResponse, emptyToken, emptyToken,
 	)
 	if err != nil {
 		t.Fatalf("DeviceListCatchup returned an error: %s", err)
diff --git a/syncapi/routing/messages.go b/syncapi/routing/messages.go
index 24745cd55..990ca55b1 100644
--- a/syncapi/routing/messages.go
+++ b/syncapi/routing/messages.go
@@ -594,6 +594,7 @@ func (r *messagesReq) backfill(roomID string, backwardsExtremities map[string][]
 			[]string{},
 			[]string{},
 			nil, true,
+			gomatrixserverlib.HistoryVisibilityShared,
 		)
 		if err != nil {
 			return nil, err
diff --git a/syncapi/storage/interface.go b/syncapi/storage/interface.go
index 5a036d889..9751670b2 100644
--- a/syncapi/storage/interface.go
+++ b/syncapi/storage/interface.go
@@ -27,6 +27,8 @@ import (
 
 type Database interface {
 	Presence
+	SharedUsers
+
 	MaxStreamPositionForPDUs(ctx context.Context) (types.StreamPosition, error)
 	MaxStreamPositionForReceipts(ctx context.Context) (types.StreamPosition, error)
 	MaxStreamPositionForInvites(ctx context.Context) (types.StreamPosition, error)
@@ -67,7 +69,9 @@ type Database interface {
 	// when generating the sync stream position for this event. Returns the sync stream position for the inserted event.
 	// Returns an error if there was a problem inserting this event.
 	WriteEvent(ctx context.Context, ev *gomatrixserverlib.HeaderedEvent, addStateEvents []*gomatrixserverlib.HeaderedEvent,
-		addStateEventIDs []string, removeStateEventIDs []string, transactionID *api.TransactionID, excludeFromSync bool) (types.StreamPosition, error)
+		addStateEventIDs []string, removeStateEventIDs []string, transactionID *api.TransactionID, excludeFromSync bool,
+		historyVisibility gomatrixserverlib.HistoryVisibility,
+	) (types.StreamPosition, error)
 	// PurgeRoomState completely purges room state from the sync API. This is done when
 	// receiving an output event that completely resets the state.
 	PurgeRoomState(ctx context.Context, roomID string) error
@@ -165,3 +169,8 @@ type Presence interface {
 	PresenceAfter(ctx context.Context, after types.StreamPosition, filter gomatrixserverlib.EventFilter) (map[string]*types.PresenceInternal, error)
 	MaxStreamPositionForPresence(ctx context.Context) (types.StreamPosition, error)
 }
+
+type SharedUsers interface {
+	// SharedUsers returns a subset of otherUserIDs that share a room with userID.
+	SharedUsers(ctx context.Context, userID string, otherUserIDs []string) ([]string, error)
+}
diff --git a/syncapi/storage/postgres/current_room_state_table.go b/syncapi/storage/postgres/current_room_state_table.go
index 8ee387b39..aae2d8c33 100644
--- a/syncapi/storage/postgres/current_room_state_table.go
+++ b/syncapi/storage/postgres/current_room_state_table.go
@@ -51,6 +51,7 @@ CREATE TABLE IF NOT EXISTS syncapi_current_room_state (
     -- The serial ID of the output_room_events table when this event became
     -- part of the current state of the room.
     added_at BIGINT,
+    history_visibility SMALLINT NOT NULL DEFAULT 2,
     -- Clobber based on 3-uple of room_id, type and state_key
     CONSTRAINT syncapi_room_state_unique UNIQUE (room_id, type, state_key)
 );
@@ -63,8 +64,8 @@ CREATE UNIQUE INDEX IF NOT EXISTS syncapi_current_room_state_eventid_idx ON sync
 `
 
 const upsertRoomStateSQL = "" +
-	"INSERT INTO syncapi_current_room_state (room_id, event_id, type, sender, contains_url, state_key, headered_event_json, membership, added_at)" +
-	" VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)" +
+	"INSERT INTO syncapi_current_room_state (room_id, event_id, type, sender, contains_url, state_key, headered_event_json, membership, added_at, history_visibility)" +
+	" VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)" +
 	" ON CONFLICT ON CONSTRAINT syncapi_room_state_unique" +
 	" DO UPDATE SET event_id = $2, sender=$4, contains_url=$5, headered_event_json = $7, membership = $8, added_at = $9"
 
@@ -100,13 +101,18 @@ const selectStateEventSQL = "" +
 	"SELECT headered_event_json FROM syncapi_current_room_state WHERE room_id = $1 AND type = $2 AND state_key = $3"
 
 const selectEventsWithEventIDsSQL = "" +
-	// TODO: The session_id and transaction_id blanks are here because otherwise
-	// the rowsToStreamEvents expects there to be exactly six columns. We need to
+	// TODO: The session_id and transaction_id blanks are here because
+	// the rowsToStreamEvents expects there to be exactly seven columns. We need to
 	// figure out if these really need to be in the DB, and if so, we need a
 	// better permanent fix for this. - neilalexander, 2 Jan 2020
-	"SELECT event_id, added_at, headered_event_json, 0 AS session_id, false AS exclude_from_sync, '' AS transaction_id" +
+	"SELECT event_id, added_at, headered_event_json, 0 AS session_id, false AS exclude_from_sync, '' AS transaction_id, history_visibility" +
 	" FROM syncapi_current_room_state WHERE event_id = ANY($1)"
 
+const selectSharedUsersSQL = "" +
+	"SELECT state_key FROM syncapi_current_room_state WHERE room_id = ANY(" +
+	"	SELECT room_id FROM syncapi_current_room_state WHERE state_key = $1 AND membership='join'" +
+	") AND state_key = ANY($2) AND membership='join';"
+
 type currentRoomStateStatements struct {
 	upsertRoomStateStmt                *sql.Stmt
 	deleteRoomStateByEventIDStmt       *sql.Stmt
@@ -118,6 +124,7 @@ type currentRoomStateStatements struct {
 	selectJoinedUsersInRoomStmt        *sql.Stmt
 	selectEventsWithEventIDsStmt       *sql.Stmt
 	selectStateEventStmt               *sql.Stmt
+	selectSharedUsersStmt              *sql.Stmt
 }
 
 func NewPostgresCurrentRoomStateTable(db *sql.DB) (tables.CurrentRoomState, error) {
@@ -156,6 +163,9 @@ func NewPostgresCurrentRoomStateTable(db *sql.DB) (tables.CurrentRoomState, erro
 	if s.selectStateEventStmt, err = db.Prepare(selectStateEventSQL); err != nil {
 		return nil, err
 	}
+	if s.selectSharedUsersStmt, err = db.Prepare(selectSharedUsersSQL); err != nil {
+		return nil, err
+	}
 	return s, nil
 }
 
@@ -327,6 +337,7 @@ func (s *currentRoomStateStatements) UpsertRoomState(
 		headeredJSON,
 		membership,
 		addedAt,
+		event.Visibility,
 	)
 	return err
 }
@@ -379,3 +390,24 @@ func (s *currentRoomStateStatements) SelectStateEvent(
 	}
 	return &ev, err
 }
+
+func (s *currentRoomStateStatements) SelectSharedUsers(
+	ctx context.Context, txn *sql.Tx, userID string, otherUserIDs []string,
+) ([]string, error) {
+	stmt := sqlutil.TxStmt(txn, s.selectSharedUsersStmt)
+	rows, err := stmt.QueryContext(ctx, userID, otherUserIDs)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectSharedUsersStmt: rows.close() failed")
+
+	var stateKey string
+	result := make([]string, 0, len(otherUserIDs))
+	for rows.Next() {
+		if err := rows.Scan(&stateKey); err != nil {
+			return nil, err
+		}
+		result = append(result, stateKey)
+	}
+	return result, rows.Err()
+}
diff --git a/syncapi/storage/postgres/deltas/2022061412000000_history_visibility_column.go b/syncapi/storage/postgres/deltas/2022061412000000_history_visibility_column.go
new file mode 100644
index 000000000..2b4b65287
--- /dev/null
+++ b/syncapi/storage/postgres/deltas/2022061412000000_history_visibility_column.go
@@ -0,0 +1,50 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package deltas
+
+import (
+	"database/sql"
+	"fmt"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+func LoadAddHistoryVisibilityColumn(m *sqlutil.Migrations) {
+	m.AddMigration(UpAddHistoryVisibilityColumn, DownAddHistoryVisibilityColumn)
+}
+
+func UpAddHistoryVisibilityColumn(tx *sql.Tx) error {
+	_, err := tx.Exec(`
+		ALTER TABLE syncapi_output_room_events ADD COLUMN IF NOT EXISTS history_visibility SMALLINT NOT NULL DEFAULT 2;
+		UPDATE syncapi_output_room_events SET history_visibility = 4 WHERE type IN ('m.room.message', 'm.room.encrypted');
+		ALTER TABLE syncapi_current_room_state ADD COLUMN IF NOT EXISTS history_visibility SMALLINT NOT NULL DEFAULT 2;
+		UPDATE syncapi_current_room_state SET history_visibility = 4 WHERE type IN ('m.room.message', 'm.room.encrypted');
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute upgrade: %w", err)
+	}
+	return nil
+}
+
+func DownAddHistoryVisibilityColumn(tx *sql.Tx) error {
+	_, err := tx.Exec(`
+		ALTER TABLE syncapi_output_room_events DROP COLUMN IF EXISTS history_visibility;
+		ALTER TABLE syncapi_current_room_state DROP COLUMN IF EXISTS history_visibility;
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute downgrade: %w", err)
+	}
+	return nil
+}
diff --git a/syncapi/storage/postgres/output_room_events_table.go b/syncapi/storage/postgres/output_room_events_table.go
index d84d0cfa2..ddef27383 100644
--- a/syncapi/storage/postgres/output_room_events_table.go
+++ b/syncapi/storage/postgres/output_room_events_table.go
@@ -67,7 +67,9 @@ CREATE TABLE IF NOT EXISTS syncapi_output_room_events (
   -- events retrieved through backfilling that have a position in the stream
   -- that relates to the moment these were retrieved rather than the moment these
   -- were emitted.
-  exclude_from_sync BOOL DEFAULT FALSE
+  exclude_from_sync BOOL DEFAULT FALSE,
+  -- The history visibility before this event (1 - world_readable; 2 - shared; 3 - invited; 4 - joined)
+  history_visibility SMALLINT NOT NULL DEFAULT 2
 );
 
 CREATE INDEX IF NOT EXISTS syncapi_output_room_events_type_idx ON syncapi_output_room_events (type);
@@ -78,16 +80,16 @@ CREATE INDEX IF NOT EXISTS syncapi_output_room_events_exclude_from_sync_idx ON s
 
 const insertEventSQL = "" +
 	"INSERT INTO syncapi_output_room_events (" +
-	"room_id, event_id, headered_event_json, type, sender, contains_url, add_state_ids, remove_state_ids, session_id, transaction_id, exclude_from_sync" +
-	") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11) " +
+	"room_id, event_id, headered_event_json, type, sender, contains_url, add_state_ids, remove_state_ids, session_id, transaction_id, exclude_from_sync, history_visibility" +
+	") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12) " +
 	"ON CONFLICT ON CONSTRAINT syncapi_event_id_idx DO UPDATE SET exclude_from_sync = (excluded.exclude_from_sync AND $11) " +
 	"RETURNING id"
 
 const selectEventsSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events WHERE event_id = ANY($1)"
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events WHERE event_id = ANY($1)"
 
 const selectEventsWithFilterSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events WHERE event_id = ANY($1)" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events WHERE event_id = ANY($1)" +
 	" AND ( $2::text[] IS NULL OR     sender  = ANY($2)  )" +
 	" AND ( $3::text[] IS NULL OR NOT(sender  = ANY($3)) )" +
 	" AND ( $4::text[] IS NULL OR     type LIKE ANY($4)  )" +
@@ -96,7 +98,7 @@ const selectEventsWithFilterSQL = "" +
 	" LIMIT $7"
 
 const selectRecentEventsSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events" +
 	" WHERE room_id = $1 AND id > $2 AND id <= $3" +
 	" AND ( $4::text[] IS NULL OR     sender  = ANY($4)  )" +
 	" AND ( $5::text[] IS NULL OR NOT(sender  = ANY($5)) )" +
@@ -105,7 +107,7 @@ const selectRecentEventsSQL = "" +
 	" ORDER BY id DESC LIMIT $8"
 
 const selectRecentEventsForSyncSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events" +
 	" WHERE room_id = $1 AND id > $2 AND id <= $3 AND exclude_from_sync = FALSE" +
 	" AND ( $4::text[] IS NULL OR     sender  = ANY($4)  )" +
 	" AND ( $5::text[] IS NULL OR NOT(sender  = ANY($5)) )" +
@@ -114,7 +116,7 @@ const selectRecentEventsForSyncSQL = "" +
 	" ORDER BY id DESC LIMIT $8"
 
 const selectEarlyEventsSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events" +
 	" WHERE room_id = $1 AND id > $2 AND id <= $3" +
 	" AND ( $4::text[] IS NULL OR     sender  = ANY($4)  )" +
 	" AND ( $5::text[] IS NULL OR NOT(sender  = ANY($5)) )" +
@@ -130,7 +132,7 @@ const updateEventJSONSQL = "" +
 
 // In order for us to apply the state updates correctly, rows need to be ordered in the order they were received (id).
 const selectStateInRangeSQL = "" +
-	"SELECT event_id, id, headered_event_json, exclude_from_sync, add_state_ids, remove_state_ids" +
+	"SELECT event_id, id, headered_event_json, exclude_from_sync, add_state_ids, remove_state_ids, history_visibility" +
 	" FROM syncapi_output_room_events" +
 	" WHERE (id > $1 AND id <= $2) AND (add_state_ids IS NOT NULL OR remove_state_ids IS NOT NULL)" +
 	" AND room_id = ANY($3)" +
@@ -146,10 +148,10 @@ const deleteEventsForRoomSQL = "" +
 	"DELETE FROM syncapi_output_room_events WHERE room_id = $1"
 
 const selectContextEventSQL = "" +
-	"SELECT id, headered_event_json FROM syncapi_output_room_events WHERE room_id = $1 AND event_id = $2"
+	"SELECT id, headered_event_json, history_visibility FROM syncapi_output_room_events WHERE room_id = $1 AND event_id = $2"
 
 const selectContextBeforeEventSQL = "" +
-	"SELECT headered_event_json FROM syncapi_output_room_events WHERE room_id = $1 AND id < $2" +
+	"SELECT headered_event_json, history_visibility FROM syncapi_output_room_events WHERE room_id = $1 AND id < $2" +
 	" AND ( $4::text[] IS NULL OR     sender  = ANY($4)  )" +
 	" AND ( $5::text[] IS NULL OR NOT(sender  = ANY($5)) )" +
 	" AND ( $6::text[] IS NULL OR     type LIKE ANY($6)  )" +
@@ -157,7 +159,7 @@ const selectContextBeforeEventSQL = "" +
 	" ORDER BY id DESC LIMIT $3"
 
 const selectContextAfterEventSQL = "" +
-	"SELECT id, headered_event_json FROM syncapi_output_room_events WHERE room_id = $1 AND id > $2" +
+	"SELECT id, headered_event_json, history_visibility FROM syncapi_output_room_events WHERE room_id = $1 AND id > $2" +
 	" AND ( $4::text[] IS NULL OR     sender  = ANY($4)  )" +
 	" AND ( $5::text[] IS NULL OR NOT(sender  = ANY($5)) )" +
 	" AND ( $6::text[] IS NULL OR     type LIKE ANY($6)  )" +
@@ -246,14 +248,15 @@ func (s *outputRoomEventsStatements) SelectStateInRange(
 
 	for rows.Next() {
 		var (
-			eventID         string
-			streamPos       types.StreamPosition
-			eventBytes      []byte
-			excludeFromSync bool
-			addIDs          pq.StringArray
-			delIDs          pq.StringArray
+			eventID           string
+			streamPos         types.StreamPosition
+			eventBytes        []byte
+			excludeFromSync   bool
+			addIDs            pq.StringArray
+			delIDs            pq.StringArray
+			historyVisibility gomatrixserverlib.HistoryVisibility
 		)
-		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &excludeFromSync, &addIDs, &delIDs); err != nil {
+		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &excludeFromSync, &addIDs, &delIDs, &historyVisibility); err != nil {
 			return nil, nil, err
 		}
 		// Sanity check for deleted state and whine if we see it. We don't need to do anything
@@ -283,6 +286,7 @@ func (s *outputRoomEventsStatements) SelectStateInRange(
 			needSet[id] = true
 		}
 		stateNeeded[ev.RoomID()] = needSet
+		ev.Visibility = historyVisibility
 
 		eventIDToEvent[eventID] = types.StreamEvent{
 			HeaderedEvent:   &ev,
@@ -314,7 +318,7 @@ func (s *outputRoomEventsStatements) SelectMaxEventID(
 func (s *outputRoomEventsStatements) InsertEvent(
 	ctx context.Context, txn *sql.Tx,
 	event *gomatrixserverlib.HeaderedEvent, addState, removeState []string,
-	transactionID *api.TransactionID, excludeFromSync bool,
+	transactionID *api.TransactionID, excludeFromSync bool, historyVisibility gomatrixserverlib.HistoryVisibility,
 ) (streamPos types.StreamPosition, err error) {
 	var txnID *string
 	var sessionID *int64
@@ -351,6 +355,7 @@ func (s *outputRoomEventsStatements) InsertEvent(
 		sessionID,
 		txnID,
 		excludeFromSync,
+		historyVisibility,
 	).Scan(&streamPos)
 	return
 }
@@ -504,13 +509,15 @@ func (s *outputRoomEventsStatements) SelectContextEvent(ctx context.Context, txn
 	row := sqlutil.TxStmt(txn, s.selectContextEventStmt).QueryRowContext(ctx, roomID, eventID)
 
 	var eventAsString string
-	if err = row.Scan(&id, &eventAsString); err != nil {
+	var historyVisibility gomatrixserverlib.HistoryVisibility
+	if err = row.Scan(&id, &eventAsString, &historyVisibility); err != nil {
 		return 0, evt, err
 	}
 
 	if err = json.Unmarshal([]byte(eventAsString), &evt); err != nil {
 		return 0, evt, err
 	}
+	evt.Visibility = historyVisibility
 	return id, evt, nil
 }
 
@@ -532,15 +539,17 @@ func (s *outputRoomEventsStatements) SelectContextBeforeEvent(
 
 	for rows.Next() {
 		var (
-			eventBytes []byte
-			evt        *gomatrixserverlib.HeaderedEvent
+			eventBytes        []byte
+			evt               *gomatrixserverlib.HeaderedEvent
+			historyVisibility gomatrixserverlib.HistoryVisibility
 		)
-		if err = rows.Scan(&eventBytes); err != nil {
+		if err = rows.Scan(&eventBytes, &historyVisibility); err != nil {
 			return evts, err
 		}
 		if err = json.Unmarshal(eventBytes, &evt); err != nil {
 			return evts, err
 		}
+		evt.Visibility = historyVisibility
 		evts = append(evts, evt)
 	}
 
@@ -565,15 +574,17 @@ func (s *outputRoomEventsStatements) SelectContextAfterEvent(
 
 	for rows.Next() {
 		var (
-			eventBytes []byte
-			evt        *gomatrixserverlib.HeaderedEvent
+			eventBytes        []byte
+			evt               *gomatrixserverlib.HeaderedEvent
+			historyVisibility gomatrixserverlib.HistoryVisibility
 		)
-		if err = rows.Scan(&lastID, &eventBytes); err != nil {
+		if err = rows.Scan(&lastID, &eventBytes, &historyVisibility); err != nil {
 			return 0, evts, err
 		}
 		if err = json.Unmarshal(eventBytes, &evt); err != nil {
 			return 0, evts, err
 		}
+		evt.Visibility = historyVisibility
 		evts = append(evts, evt)
 	}
 
@@ -584,15 +595,16 @@ func rowsToStreamEvents(rows *sql.Rows) ([]types.StreamEvent, error) {
 	var result []types.StreamEvent
 	for rows.Next() {
 		var (
-			eventID         string
-			streamPos       types.StreamPosition
-			eventBytes      []byte
-			excludeFromSync bool
-			sessionID       *int64
-			txnID           *string
-			transactionID   *api.TransactionID
+			eventID           string
+			streamPos         types.StreamPosition
+			eventBytes        []byte
+			excludeFromSync   bool
+			sessionID         *int64
+			txnID             *string
+			transactionID     *api.TransactionID
+			historyVisibility gomatrixserverlib.HistoryVisibility
 		)
-		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &sessionID, &excludeFromSync, &txnID); err != nil {
+		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &sessionID, &excludeFromSync, &txnID, &historyVisibility); err != nil {
 			return nil, err
 		}
 		// TODO: Handle redacted events
@@ -607,7 +619,7 @@ func rowsToStreamEvents(rows *sql.Rows) ([]types.StreamEvent, error) {
 				TransactionID: *txnID,
 			}
 		}
-
+		ev.Visibility = historyVisibility
 		result = append(result, types.StreamEvent{
 			HeaderedEvent:   &ev,
 			StreamPosition:  streamPos,
diff --git a/syncapi/storage/postgres/syncserver.go b/syncapi/storage/postgres/syncserver.go
index 9cfe7c070..c6121e419 100644
--- a/syncapi/storage/postgres/syncserver.go
+++ b/syncapi/storage/postgres/syncserver.go
@@ -42,18 +42,16 @@ func NewDatabase(base *base.BaseDendrite, dbProperties *config.DatabaseOptions)
 	if d.db, d.writer, err = base.DatabaseConnection(dbProperties, sqlutil.NewDummyWriter()); err != nil {
 		return nil, err
 	}
+	if _, err = d.db.Exec(outputRoomEventsSchema); err != nil {
+		return nil, err
+	}
+	if _, err = d.db.Exec(currentRoomStateSchema); err != nil {
+		return nil, err
+	}
 	accountData, err := NewPostgresAccountDataTable(d.db)
 	if err != nil {
 		return nil, err
 	}
-	events, err := NewPostgresEventsTable(d.db)
-	if err != nil {
-		return nil, err
-	}
-	currState, err := NewPostgresCurrentRoomStateTable(d.db)
-	if err != nil {
-		return nil, err
-	}
 	invites, err := NewPostgresInvitesTable(d.db)
 	if err != nil {
 		return nil, err
@@ -101,9 +99,19 @@ func NewDatabase(base *base.BaseDendrite, dbProperties *config.DatabaseOptions)
 	m := sqlutil.NewMigrations()
 	deltas.LoadFixSequences(m)
 	deltas.LoadRemoveSendToDeviceSentColumn(m)
+	deltas.LoadAddHistoryVisibilityColumn(m)
 	if err = m.RunDeltas(d.db, dbProperties); err != nil {
 		return nil, err
 	}
+	// prepare statements after the migrations have run
+	events, err := NewPostgresEventsTable(d.db)
+	if err != nil {
+		return nil, err
+	}
+	currState, err := NewPostgresCurrentRoomStateTable(d.db)
+	if err != nil {
+		return nil, err
+	}
 	d.Database = shared.Database{
 		DB:                  d.db,
 		Writer:              d.writer,
diff --git a/syncapi/storage/shared/syncserver.go b/syncapi/storage/shared/syncserver.go
index 76114aff8..932bda164 100644
--- a/syncapi/storage/shared/syncserver.go
+++ b/syncapi/storage/shared/syncserver.go
@@ -176,6 +176,10 @@ func (d *Database) AllPeekingDevicesInRooms(ctx context.Context) (map[string][]t
 	return d.Peeks.SelectPeekingDevices(ctx)
 }
 
+func (d *Database) SharedUsers(ctx context.Context, userID string, otherUserIDs []string) ([]string, error) {
+	return d.CurrentRoomState.SelectSharedUsers(ctx, nil, userID, otherUserIDs)
+}
+
 func (d *Database) GetStateEvent(
 	ctx context.Context, roomID, evType, stateKey string,
 ) (*gomatrixserverlib.HeaderedEvent, error) {
@@ -364,11 +368,12 @@ func (d *Database) WriteEvent(
 	addStateEvents []*gomatrixserverlib.HeaderedEvent,
 	addStateEventIDs, removeStateEventIDs []string,
 	transactionID *api.TransactionID, excludeFromSync bool,
+	historyVisibility gomatrixserverlib.HistoryVisibility,
 ) (pduPosition types.StreamPosition, returnErr error) {
 	returnErr = d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
 		var err error
 		pos, err := d.OutputEvents.InsertEvent(
-			ctx, txn, ev, addStateEventIDs, removeStateEventIDs, transactionID, excludeFromSync,
+			ctx, txn, ev, addStateEventIDs, removeStateEventIDs, transactionID, excludeFromSync, historyVisibility,
 		)
 		if err != nil {
 			return fmt.Errorf("d.OutputEvents.InsertEvent: %w", err)
@@ -387,7 +392,9 @@ func (d *Database) WriteEvent(
 			// Nothing to do, the event may have just been a message event.
 			return nil
 		}
-
+		for i := range addStateEvents {
+			addStateEvents[i].Visibility = historyVisibility
+		}
 		return d.updateRoomState(ctx, txn, removeStateEventIDs, addStateEvents, pduPosition, topoPosition)
 	})
 
diff --git a/syncapi/storage/sqlite3/current_room_state_table.go b/syncapi/storage/sqlite3/current_room_state_table.go
index f0a1c7bb7..501d0ee98 100644
--- a/syncapi/storage/sqlite3/current_room_state_table.go
+++ b/syncapi/storage/sqlite3/current_room_state_table.go
@@ -41,6 +41,7 @@ CREATE TABLE IF NOT EXISTS syncapi_current_room_state (
     headered_event_json TEXT NOT NULL,
     membership TEXT,
     added_at BIGINT,
+    history_visibility SMALLINT NOT NULL DEFAULT 2, -- The history visibility before this event (1 - world_readable; 2 - shared; 3 - invited; 4 - joined)
     UNIQUE (room_id, type, state_key)
 );
 -- for event deletion
@@ -52,8 +53,8 @@ CREATE UNIQUE INDEX IF NOT EXISTS syncapi_current_room_state_eventid_idx ON sync
 `
 
 const upsertRoomStateSQL = "" +
-	"INSERT INTO syncapi_current_room_state (room_id, event_id, type, sender, contains_url, state_key, headered_event_json, membership, added_at)" +
-	" VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)" +
+	"INSERT INTO syncapi_current_room_state (room_id, event_id, type, sender, contains_url, state_key, headered_event_json, membership, added_at, history_visibility)" +
+	" VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)" +
 	" ON CONFLICT (room_id, type, state_key)" +
 	" DO UPDATE SET event_id = $2, sender=$4, contains_url=$5, headered_event_json = $7, membership = $8, added_at = $9"
 
@@ -84,13 +85,18 @@ const selectStateEventSQL = "" +
 	"SELECT headered_event_json FROM syncapi_current_room_state WHERE room_id = $1 AND type = $2 AND state_key = $3"
 
 const selectEventsWithEventIDsSQL = "" +
-	// TODO: The session_id and transaction_id blanks are here because otherwise
-	// the rowsToStreamEvents expects there to be exactly six columns. We need to
+	// TODO: The session_id and transaction_id blanks are here because
+	// the rowsToStreamEvents expects there to be exactly seven columns. We need to
 	// figure out if these really need to be in the DB, and if so, we need a
 	// better permanent fix for this. - neilalexander, 2 Jan 2020
-	"SELECT event_id, added_at, headered_event_json, 0 AS session_id, false AS exclude_from_sync, '' AS transaction_id" +
+	"SELECT event_id, added_at, headered_event_json, 0 AS session_id, false AS exclude_from_sync, '' AS transaction_id, history_visibility" +
 	" FROM syncapi_current_room_state WHERE event_id IN ($1)"
 
+const selectSharedUsersSQL = "" +
+	"SELECT state_key FROM syncapi_current_room_state WHERE room_id = ANY(" +
+	"	SELECT room_id FROM syncapi_current_room_state WHERE state_key = $1 AND membership='join'" +
+	") AND state_key IN ($2) AND membership='join';"
+
 type currentRoomStateStatements struct {
 	db                                 *sql.DB
 	streamIDStatements                 *StreamIDStatements
@@ -100,8 +106,9 @@ type currentRoomStateStatements struct {
 	selectRoomIDsWithMembershipStmt    *sql.Stmt
 	selectRoomIDsWithAnyMembershipStmt *sql.Stmt
 	selectJoinedUsersStmt              *sql.Stmt
-	//selectJoinedUsersInRoomStmt        *sql.Stmt - prepared at runtime due to variadic
+	//selectJoinedUsersInRoomStmt      *sql.Stmt - prepared at runtime due to variadic
 	selectStateEventStmt *sql.Stmt
+	//selectSharedUsersSQL             *sql.Stmt - prepared at runtime due to variadic
 }
 
 func NewSqliteCurrentRoomStateTable(db *sql.DB, streamID *StreamIDStatements) (tables.CurrentRoomState, error) {
@@ -322,6 +329,7 @@ func (s *currentRoomStateStatements) UpsertRoomState(
 		headeredJSON,
 		membership,
 		addedAt,
+		event.Visibility,
 	)
 	return err
 }
@@ -396,3 +404,29 @@ func (s *currentRoomStateStatements) SelectStateEvent(
 	}
 	return &ev, err
 }
+
+func (s *currentRoomStateStatements) SelectSharedUsers(
+	ctx context.Context, txn *sql.Tx, userID string, otherUserIDs []string,
+) ([]string, error) {
+	query := strings.Replace(selectSharedUsersSQL, "($2)", sqlutil.QueryVariadicOffset(len(otherUserIDs), 1), 1)
+	stmt, err := s.db.Prepare(query)
+	if err != nil {
+		return nil, fmt.Errorf("SelectSharedUsers s.db.Prepare: %w", err)
+	}
+	defer internal.CloseAndLogIfError(ctx, stmt, "SelectSharedUsers: stmt.close() failed")
+	rows, err := sqlutil.TxStmt(txn, stmt).QueryContext(ctx, userID, otherUserIDs)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "selectSharedUsersStmt: rows.close() failed")
+
+	var stateKey string
+	result := make([]string, 0, len(otherUserIDs))
+	for rows.Next() {
+		if err := rows.Scan(&stateKey); err != nil {
+			return nil, err
+		}
+		result = append(result, stateKey)
+	}
+	return result, rows.Err()
+}
diff --git a/syncapi/storage/sqlite3/deltas/2022061412000000_history_visibility_column.go b/syncapi/storage/sqlite3/deltas/2022061412000000_history_visibility_column.go
new file mode 100644
index 000000000..f6bcaddfb
--- /dev/null
+++ b/syncapi/storage/sqlite3/deltas/2022061412000000_history_visibility_column.go
@@ -0,0 +1,82 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package deltas
+
+import (
+	"database/sql"
+	"fmt"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+)
+
+func LoadAddHistoryVisibilityColumn(m *sqlutil.Migrations) {
+	m.AddMigration(UpAddHistoryVisibilityColumn, DownAddHistoryVisibilityColumn)
+}
+
+func UpAddHistoryVisibilityColumn(tx *sql.Tx) error {
+	// SQLite doesn't have "if exists", so check if the column exists. If the query doesn't return an error, it already exists.
+	// Required for unit tests, as otherwise a duplicate column error will show up.
+	_, err := tx.Query("SELECT history_visibility FROM syncapi_output_room_events LIMIT 1")
+	if err == nil {
+		return nil
+	}
+	_, err = tx.Exec(`
+		ALTER TABLE syncapi_output_room_events ADD COLUMN history_visibility SMALLINT NOT NULL DEFAULT 2;
+		UPDATE syncapi_output_room_events SET history_visibility = 4 WHERE type IN ('m.room.message', 'm.room.encrypted');
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute upgrade: %w", err)
+	}
+
+	_, err = tx.Query("SELECT history_visibility FROM syncapi_current_room_state LIMIT 1")
+	if err == nil {
+		return nil
+	}
+	_, err = tx.Exec(`
+		ALTER TABLE syncapi_current_room_state ADD COLUMN history_visibility SMALLINT NOT NULL DEFAULT 2;
+		UPDATE syncapi_current_room_state SET history_visibility = 4 WHERE type IN ('m.room.message', 'm.room.encrypted');
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute upgrade: %w", err)
+	}
+	return nil
+}
+
+func DownAddHistoryVisibilityColumn(tx *sql.Tx) error {
+	// SQLite doesn't have "if exists", so check if the column exists.
+	_, err := tx.Query("SELECT history_visibility FROM syncapi_output_room_events LIMIT 1")
+	if err != nil {
+		// The column probably doesn't exist
+		return nil
+	}
+	_, err = tx.Exec(`
+		ALTER TABLE syncapi_output_room_events DROP COLUMN history_visibility;
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute downgrade: %w", err)
+	}
+	_, err = tx.Query("SELECT history_visibility FROM syncapi_current_room_state LIMIT 1")
+	if err != nil {
+		// The column probably doesn't exist
+		return nil
+	}
+	_, err = tx.Exec(`
+		ALTER TABLE syncapi_current_room_state DROP COLUMN history_visibility;
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute downgrade: %w", err)
+	}
+	return nil
+}
diff --git a/syncapi/storage/sqlite3/output_room_events_table.go b/syncapi/storage/sqlite3/output_room_events_table.go
index f9961a9d1..b3dcb44cb 100644
--- a/syncapi/storage/sqlite3/output_room_events_table.go
+++ b/syncapi/storage/sqlite3/output_room_events_table.go
@@ -47,7 +47,8 @@ CREATE TABLE IF NOT EXISTS syncapi_output_room_events (
   remove_state_ids TEXT, -- JSON encoded string array
   session_id BIGINT,
   transaction_id TEXT,
-  exclude_from_sync BOOL NOT NULL DEFAULT FALSE
+  exclude_from_sync BOOL NOT NULL DEFAULT FALSE,
+  history_visibility SMALLINT NOT NULL DEFAULT 2 -- The history visibility before this event (1 - world_readable; 2 - shared; 3 - invited; 4 - joined)
 );
 
 CREATE INDEX IF NOT EXISTS syncapi_output_room_events_type_idx ON syncapi_output_room_events (type);
@@ -58,27 +59,27 @@ CREATE INDEX IF NOT EXISTS syncapi_output_room_events_exclude_from_sync_idx ON s
 
 const insertEventSQL = "" +
 	"INSERT INTO syncapi_output_room_events (" +
-	"id, room_id, event_id, headered_event_json, type, sender, contains_url, add_state_ids, remove_state_ids, session_id, transaction_id, exclude_from_sync" +
-	") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12) " +
-	"ON CONFLICT (event_id) DO UPDATE SET exclude_from_sync = (excluded.exclude_from_sync AND $13)"
+	"id, room_id, event_id, headered_event_json, type, sender, contains_url, add_state_ids, remove_state_ids, session_id, transaction_id, exclude_from_sync, history_visibility" +
+	") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13) " +
+	"ON CONFLICT (event_id) DO UPDATE SET exclude_from_sync = (excluded.exclude_from_sync AND $14)"
 
 const selectEventsSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events WHERE event_id IN ($1)"
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events WHERE event_id IN ($1)"
 
 const selectRecentEventsSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events" +
 	" WHERE room_id = $1 AND id > $2 AND id <= $3"
 
 // WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
 
 const selectRecentEventsForSyncSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events" +
 	" WHERE room_id = $1 AND id > $2 AND id <= $3 AND exclude_from_sync = FALSE"
 
 // WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
 
 const selectEarlyEventsSQL = "" +
-	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id FROM syncapi_output_room_events" +
+	"SELECT event_id, id, headered_event_json, session_id, exclude_from_sync, transaction_id, history_visibility FROM syncapi_output_room_events" +
 	" WHERE room_id = $1 AND id > $2 AND id <= $3"
 
 // WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
@@ -90,7 +91,7 @@ const updateEventJSONSQL = "" +
 	"UPDATE syncapi_output_room_events SET headered_event_json=$1 WHERE event_id=$2"
 
 const selectStateInRangeSQL = "" +
-	"SELECT event_id, id, headered_event_json, exclude_from_sync, add_state_ids, remove_state_ids" +
+	"SELECT event_id, id, headered_event_json, exclude_from_sync, add_state_ids, remove_state_ids, history_visibility" +
 	" FROM syncapi_output_room_events" +
 	" WHERE (id > $1 AND id <= $2)" +
 	" AND room_id IN ($3)" +
@@ -102,15 +103,15 @@ const deleteEventsForRoomSQL = "" +
 	"DELETE FROM syncapi_output_room_events WHERE room_id = $1"
 
 const selectContextEventSQL = "" +
-	"SELECT id, headered_event_json FROM syncapi_output_room_events WHERE room_id = $1 AND event_id = $2"
+	"SELECT id, headered_event_json, history_visibility FROM syncapi_output_room_events WHERE room_id = $1 AND event_id = $2"
 
 const selectContextBeforeEventSQL = "" +
-	"SELECT headered_event_json FROM syncapi_output_room_events WHERE room_id = $1 AND id < $2"
+	"SELECT headered_event_json, history_visibility FROM syncapi_output_room_events WHERE room_id = $1 AND id < $2"
 
 // WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
 
 const selectContextAfterEventSQL = "" +
-	"SELECT id, headered_event_json FROM syncapi_output_room_events WHERE room_id = $1 AND id > $2"
+	"SELECT id, headered_event_json, history_visibility FROM syncapi_output_room_events WHERE room_id = $1 AND id > $2"
 
 // WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
 
@@ -196,14 +197,15 @@ func (s *outputRoomEventsStatements) SelectStateInRange(
 
 	for rows.Next() {
 		var (
-			eventID         string
-			streamPos       types.StreamPosition
-			eventBytes      []byte
-			excludeFromSync bool
-			addIDsJSON      string
-			delIDsJSON      string
+			eventID           string
+			streamPos         types.StreamPosition
+			eventBytes        []byte
+			excludeFromSync   bool
+			addIDsJSON        string
+			delIDsJSON        string
+			historyVisibility gomatrixserverlib.HistoryVisibility
 		)
-		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &excludeFromSync, &addIDsJSON, &delIDsJSON); err != nil {
+		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &excludeFromSync, &addIDsJSON, &delIDsJSON, &historyVisibility); err != nil {
 			return nil, nil, err
 		}
 
@@ -239,6 +241,7 @@ func (s *outputRoomEventsStatements) SelectStateInRange(
 			needSet[id] = true
 		}
 		stateNeeded[ev.RoomID()] = needSet
+		ev.Visibility = historyVisibility
 
 		eventIDToEvent[eventID] = types.StreamEvent{
 			HeaderedEvent:   &ev,
@@ -270,7 +273,7 @@ func (s *outputRoomEventsStatements) SelectMaxEventID(
 func (s *outputRoomEventsStatements) InsertEvent(
 	ctx context.Context, txn *sql.Tx,
 	event *gomatrixserverlib.HeaderedEvent, addState, removeState []string,
-	transactionID *api.TransactionID, excludeFromSync bool,
+	transactionID *api.TransactionID, excludeFromSync bool, historyVisibility gomatrixserverlib.HistoryVisibility,
 ) (types.StreamPosition, error) {
 	var txnID *string
 	var sessionID *int64
@@ -326,6 +329,7 @@ func (s *outputRoomEventsStatements) InsertEvent(
 		sessionID,
 		txnID,
 		excludeFromSync,
+		historyVisibility,
 		excludeFromSync,
 	)
 	return streamPos, err
@@ -481,15 +485,16 @@ func rowsToStreamEvents(rows *sql.Rows) ([]types.StreamEvent, error) {
 	var result []types.StreamEvent
 	for rows.Next() {
 		var (
-			eventID         string
-			streamPos       types.StreamPosition
-			eventBytes      []byte
-			excludeFromSync bool
-			sessionID       *int64
-			txnID           *string
-			transactionID   *api.TransactionID
+			eventID           string
+			streamPos         types.StreamPosition
+			eventBytes        []byte
+			excludeFromSync   bool
+			sessionID         *int64
+			txnID             *string
+			transactionID     *api.TransactionID
+			historyVisibility gomatrixserverlib.HistoryVisibility
 		)
-		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &sessionID, &excludeFromSync, &txnID); err != nil {
+		if err := rows.Scan(&eventID, &streamPos, &eventBytes, &sessionID, &excludeFromSync, &txnID, &historyVisibility); err != nil {
 			return nil, err
 		}
 		// TODO: Handle redacted events
@@ -505,6 +510,8 @@ func rowsToStreamEvents(rows *sql.Rows) ([]types.StreamEvent, error) {
 			}
 		}
 
+		ev.Visibility = historyVisibility
+
 		result = append(result, types.StreamEvent{
 			HeaderedEvent:   &ev,
 			StreamPosition:  streamPos,
@@ -519,13 +526,15 @@ func (s *outputRoomEventsStatements) SelectContextEvent(
 ) (id int, evt gomatrixserverlib.HeaderedEvent, err error) {
 	row := sqlutil.TxStmt(txn, s.selectContextEventStmt).QueryRowContext(ctx, roomID, eventID)
 	var eventAsString string
-	if err = row.Scan(&id, &eventAsString); err != nil {
+	var historyVisibility gomatrixserverlib.HistoryVisibility
+	if err = row.Scan(&id, &eventAsString, &historyVisibility); err != nil {
 		return 0, evt, err
 	}
 
 	if err = json.Unmarshal([]byte(eventAsString), &evt); err != nil {
 		return 0, evt, err
 	}
+	evt.Visibility = historyVisibility
 	return id, evt, nil
 }
 
@@ -550,15 +559,17 @@ func (s *outputRoomEventsStatements) SelectContextBeforeEvent(
 
 	for rows.Next() {
 		var (
-			eventBytes []byte
-			evt        *gomatrixserverlib.HeaderedEvent
+			eventBytes        []byte
+			evt               *gomatrixserverlib.HeaderedEvent
+			historyVisibility gomatrixserverlib.HistoryVisibility
 		)
-		if err = rows.Scan(&eventBytes); err != nil {
+		if err = rows.Scan(&eventBytes, &historyVisibility); err != nil {
 			return evts, err
 		}
 		if err = json.Unmarshal(eventBytes, &evt); err != nil {
 			return evts, err
 		}
+		evt.Visibility = historyVisibility
 		evts = append(evts, evt)
 	}
 
@@ -586,15 +597,17 @@ func (s *outputRoomEventsStatements) SelectContextAfterEvent(
 
 	for rows.Next() {
 		var (
-			eventBytes []byte
-			evt        *gomatrixserverlib.HeaderedEvent
+			eventBytes        []byte
+			evt               *gomatrixserverlib.HeaderedEvent
+			historyVisibility gomatrixserverlib.HistoryVisibility
 		)
-		if err = rows.Scan(&lastID, &eventBytes); err != nil {
+		if err = rows.Scan(&lastID, &eventBytes, &historyVisibility); err != nil {
 			return 0, evts, err
 		}
 		if err = json.Unmarshal(eventBytes, &evt); err != nil {
 			return 0, evts, err
 		}
+		evt.Visibility = historyVisibility
 		evts = append(evts, evt)
 	}
 	return lastID, evts, rows.Err()
diff --git a/syncapi/storage/sqlite3/syncserver.go b/syncapi/storage/sqlite3/syncserver.go
index e08a0ba82..39ceec81d 100644
--- a/syncapi/storage/sqlite3/syncserver.go
+++ b/syncapi/storage/sqlite3/syncserver.go
@@ -52,18 +52,16 @@ func (d *SyncServerDatasource) prepare(dbProperties *config.DatabaseOptions) (er
 	if err = d.streamID.Prepare(d.db); err != nil {
 		return err
 	}
+	if _, err = d.db.Exec(outputRoomEventsSchema); err != nil {
+		return err
+	}
+	if _, err = d.db.Exec(currentRoomStateSchema); err != nil {
+		return err
+	}
 	accountData, err := NewSqliteAccountDataTable(d.db, &d.streamID)
 	if err != nil {
 		return err
 	}
-	events, err := NewSqliteEventsTable(d.db, &d.streamID)
-	if err != nil {
-		return err
-	}
-	roomState, err := NewSqliteCurrentRoomStateTable(d.db, &d.streamID)
-	if err != nil {
-		return err
-	}
 	invites, err := NewSqliteInvitesTable(d.db, &d.streamID)
 	if err != nil {
 		return err
@@ -111,9 +109,19 @@ func (d *SyncServerDatasource) prepare(dbProperties *config.DatabaseOptions) (er
 	m := sqlutil.NewMigrations()
 	deltas.LoadFixSequences(m)
 	deltas.LoadRemoveSendToDeviceSentColumn(m)
+	deltas.LoadAddHistoryVisibilityColumn(m)
 	if err = m.RunDeltas(d.db, dbProperties); err != nil {
 		return err
 	}
+	// prepare statements after the migrations have run
+	events, err := NewSqliteEventsTable(d.db, &d.streamID)
+	if err != nil {
+		return err
+	}
+	roomState, err := NewSqliteCurrentRoomStateTable(d.db, &d.streamID)
+	if err != nil {
+		return err
+	}
 	d.Database = shared.Database{
 		DB:                  d.db,
 		Writer:              d.writer,
diff --git a/syncapi/storage/storage_test.go b/syncapi/storage/storage_test.go
index c74151700..df03a33c2 100644
--- a/syncapi/storage/storage_test.go
+++ b/syncapi/storage/storage_test.go
@@ -37,7 +37,7 @@ func MustWriteEvents(t *testing.T, db storage.Database, events []*gomatrixserver
 			addStateEvents = append(addStateEvents, ev)
 			addStateEventIDs = append(addStateEventIDs, ev.EventID())
 		}
-		pos, err := db.WriteEvent(ctx, ev, addStateEvents, addStateEventIDs, removeStateEventIDs, nil, false)
+		pos, err := db.WriteEvent(ctx, ev, addStateEvents, addStateEventIDs, removeStateEventIDs, nil, false, gomatrixserverlib.HistoryVisibilityShared)
 		if err != nil {
 			t.Fatalf("WriteEvent failed: %s", err)
 		}
diff --git a/syncapi/storage/tables/interface.go b/syncapi/storage/tables/interface.go
index ccdebfdbd..d8fc8f508 100644
--- a/syncapi/storage/tables/interface.go
+++ b/syncapi/storage/tables/interface.go
@@ -52,7 +52,14 @@ type Peeks interface {
 type Events interface {
 	SelectStateInRange(ctx context.Context, txn *sql.Tx, r types.Range, stateFilter *gomatrixserverlib.StateFilter, roomIDs []string) (map[string]map[string]bool, map[string]types.StreamEvent, error)
 	SelectMaxEventID(ctx context.Context, txn *sql.Tx) (id int64, err error)
-	InsertEvent(ctx context.Context, txn *sql.Tx, event *gomatrixserverlib.HeaderedEvent, addState, removeState []string, transactionID *api.TransactionID, excludeFromSync bool) (streamPos types.StreamPosition, err error)
+	InsertEvent(
+		ctx context.Context, txn *sql.Tx,
+		event *gomatrixserverlib.HeaderedEvent,
+		addState, removeState []string,
+		transactionID *api.TransactionID,
+		excludeFromSync bool,
+		historyVisibility gomatrixserverlib.HistoryVisibility,
+	) (streamPos types.StreamPosition, err error)
 	// SelectRecentEvents returns events between the two stream positions: exclusive of low and inclusive of high.
 	// If onlySyncEvents has a value of true, only returns the events that aren't marked as to exclude from sync.
 	// Returns up to `limit` events. Returns `limited=true` if there are more events in this range but we hit the `limit`.
@@ -104,6 +111,8 @@ type CurrentRoomState interface {
 	SelectJoinedUsers(ctx context.Context) (map[string][]string, error)
 	// SelectJoinedUsersInRoom returns a map of room ID to a list of joined user IDs for a given room.
 	SelectJoinedUsersInRoom(ctx context.Context, roomIDs []string) (map[string][]string, error)
+	// SelectSharedUsers returns a subset of otherUserIDs that share a room with userID.
+	SelectSharedUsers(ctx context.Context, txn *sql.Tx, userID string, otherUserIDs []string) ([]string, error)
 }
 
 // BackwardsExtremities keeps track of backwards extremities for a room.
diff --git a/syncapi/storage/tables/output_room_events_test.go b/syncapi/storage/tables/output_room_events_test.go
index 69bbd04c9..bdb17ae20 100644
--- a/syncapi/storage/tables/output_room_events_test.go
+++ b/syncapi/storage/tables/output_room_events_test.go
@@ -53,7 +53,7 @@ func TestOutputRoomEventsTable(t *testing.T) {
 		events := room.Events()
 		err := sqlutil.WithTransaction(db, func(txn *sql.Tx) error {
 			for _, ev := range events {
-				_, err := tab.InsertEvent(ctx, txn, ev, nil, nil, nil, false)
+				_, err := tab.InsertEvent(ctx, txn, ev, nil, nil, nil, false, gomatrixserverlib.HistoryVisibilityShared)
 				if err != nil {
 					return fmt.Errorf("failed to InsertEvent: %s", err)
 				}
@@ -79,7 +79,7 @@ func TestOutputRoomEventsTable(t *testing.T) {
 				"body": "test.txt",
 				"url":  "mxc://test.txt",
 			})
-			if _, err = tab.InsertEvent(ctx, txn, urlEv, nil, nil, nil, false); err != nil {
+			if _, err = tab.InsertEvent(ctx, txn, urlEv, nil, nil, nil, false, gomatrixserverlib.HistoryVisibilityShared); err != nil {
 				return fmt.Errorf("failed to InsertEvent: %s", err)
 			}
 			wantEventID := []string{urlEv.EventID()}
diff --git a/syncapi/streams/stream_devicelist.go b/syncapi/streams/stream_devicelist.go
index f42099510..5448ee5bd 100644
--- a/syncapi/streams/stream_devicelist.go
+++ b/syncapi/streams/stream_devicelist.go
@@ -28,7 +28,7 @@ func (p *DeviceListStreamProvider) IncrementalSync(
 	from, to types.StreamPosition,
 ) types.StreamPosition {
 	var err error
-	to, _, err = internal.DeviceListCatchup(context.Background(), p.keyAPI, p.rsAPI, req.Device.UserID, req.Response, from, to)
+	to, _, err = internal.DeviceListCatchup(context.Background(), p.DB, p.keyAPI, p.rsAPI, req.Device.UserID, req.Response, from, to)
 	if err != nil {
 		req.Log.WithError(err).Error("internal.DeviceListCatchup failed")
 		return from
diff --git a/syncapi/sync/requestpool.go b/syncapi/sync/requestpool.go
index 6f0849e08..b6b4779a5 100644
--- a/syncapi/sync/requestpool.go
+++ b/syncapi/sync/requestpool.go
@@ -429,7 +429,7 @@ func (rp *RequestPool) OnIncomingKeyChangeRequest(req *http.Request, device *use
 	}
 	rp.streams.PDUStreamProvider.IncrementalSync(req.Context(), syncReq, fromToken.PDUPosition, toToken.PDUPosition)
 	_, _, err = internal.DeviceListCatchup(
-		req.Context(), rp.keyAPI, rp.rsAPI, syncReq.Device.UserID,
+		req.Context(), rp.db, rp.keyAPI, rp.rsAPI, syncReq.Device.UserID,
 		syncReq.Response, fromToken.DeviceListPosition, toToken.DeviceListPosition,
 	)
 	if err != nil {
diff --git a/userapi/util/phonehomestats.go b/userapi/util/phonehomestats.go
index ad93a50e3..b17f62060 100644
--- a/userapi/util/phonehomestats.go
+++ b/userapi/util/phonehomestats.go
@@ -139,7 +139,7 @@ func (p *phoneHomeStats) collect() {
 
 	output := bytes.Buffer{}
 	if err = json.NewEncoder(&output).Encode(p.stats); err != nil {
-		logrus.WithError(err).Error("unable to encode anonymous stats")
+		logrus.WithError(err).Error("Unable to encode phone-home statistics")
 		return
 	}
 
@@ -147,14 +147,14 @@ func (p *phoneHomeStats) collect() {
 
 	request, err := http.NewRequestWithContext(ctx, http.MethodPost, p.cfg.Global.ReportStats.Endpoint, &output)
 	if err != nil {
-		logrus.WithError(err).Error("unable to create anonymous stats request")
+		logrus.WithError(err).Error("Unable to create phone-home statistics request")
 		return
 	}
 	request.Header.Set("User-Agent", "Dendrite/"+internal.VersionString())
 
 	_, err = p.client.Do(request)
 	if err != nil {
-		logrus.WithError(err).Error("unable to send anonymous stats")
+		logrus.WithError(err).Error("Unable to send phone-home statistics")
 		return
 	}
 }