diff --git a/matrix/m.room.join_rules/README.md b/matrix/m.room.join_rules/README.md
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+# m.room.join_rules
+
+Controls who can join the room. This is best to configure in room settings.
+
+## knocking
+
+Requires room version 7
+
+```json
+{
+	"join_rule": "knock"
+}
+```
+
+## membership of another room
+
+Requires room version <del>8</del> 9. Offers only Spaces in room settings
+
+```json
+{
+	"allow": [
+		{
+			"room_id": "!oHIvaRnuEEIDavQVRJ:matrix.org",
+			"type": "m.room_membership"
+		}
+	],
+	"join_rule": "restricted"
+}
+```
+
+### membership of one of multiple rooms
+
+```json
+{
+	"allow": [
+		{
+			"room_id": "!psumPMeAfzgAeQpXMG:feneas.org",
+			"type": "m.room_membership"
+		},
+		{
+			"room_id": "!ddFNqIRUacwdicInJz:feneas.org",
+			"type": "m.room_membership"
+		}
+	],
+	"join_rule": "restricted"
+}
+```
+
+It can be presumed that multiple spaces is simply copying that more.