diff --git a/common/caching/cache.go b/common/caching/cache.go
index 09edb44f9..83404fecf 100644
--- a/common/caching/cache.go
+++ b/common/caching/cache.go
@@ -2,6 +2,10 @@ package caching
 
 import "github.com/matrix-org/gomatrixserverlib"
 
+const (
+	MaxRoomVersionCacheEntries = 128
+)
+
 type Cache interface {
 	GetRoomVersion(roomId string) (gomatrixserverlib.RoomVersion, bool)
 	StoreRoomVersion(roomId string, roomVersion gomatrixserverlib.RoomVersion)
diff --git a/common/caching/inmemorylru.go b/common/caching/inmemorylru.go
index df9295ba2..89101f4a2 100644
--- a/common/caching/inmemorylru.go
+++ b/common/caching/inmemorylru.go
@@ -10,7 +10,7 @@ type InMemoryLRUCache struct {
 }
 
 func NewInMemoryLRUCache() (*InMemoryLRUCache, error) {
-	roomVersionCache, rvErr := lru.New(128)
+	roomVersionCache, rvErr := lru.New(MaxRoomVersionCacheEntries)
 	if rvErr != nil {
 		return nil, rvErr
 	}