diff --git a/federationsender/storage/postgres/room_table.go b/federationsender/storage/postgres/room_table.go
index c7a205786..0e47aa95c 100644
--- a/federationsender/storage/postgres/room_table.go
+++ b/federationsender/storage/postgres/room_table.go
@@ -81,4 +81,3 @@ func (s *roomStatements) SelectRoomForUpdate(
 	}
 	return lastEventID, nil
 }
-
diff --git a/federationsender/types/types.go b/federationsender/types/types.go
index 90da310c9..c486c05c4 100644
--- a/federationsender/types/types.go
+++ b/federationsender/types/types.go
@@ -15,8 +15,6 @@
 package types
 
 import (
-	"fmt"
-
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
@@ -34,22 +32,6 @@ func (s ServerNames) Len() int           { return len(s) }
 func (s ServerNames) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
 func (s ServerNames) Less(i, j int) bool { return s[i] < s[j] }
 
-// A EventIDMismatchError indicates that we have got out of sync with the
-// room server.
-type EventIDMismatchError struct {
-	// The event ID we have stored in our local database.
-	DatabaseID string
-	// The event ID received from the room server.
-	RoomServerID string
-}
-
-func (e EventIDMismatchError) Error() string {
-	return fmt.Sprintf(
-		"mismatched last sent event ID: had %q in database got %q from room server",
-		e.DatabaseID, e.RoomServerID,
-	)
-}
-
 // tracks peeks we're performing on another server over federation
 type OutboundPeek struct {
 	PeekID            string