diff --git a/include/ircd/m/createroom.h b/include/ircd/m/createroom.h
index b7a46880b..efc0158d2 100644
--- a/include/ircd/m/createroom.h
+++ b/include/ircd/m/createroom.h
@@ -99,7 +99,11 @@ struct ircd::m::createroom
 
 	/// (non-spec) Manually specify the room creator. This is an interface
 	/// convenience and will be overwritten/ignored from unprivileged users.
-	json::property<name::creator, json::string>
+	json::property<name::creator, json::string>,
+
+	/// (non-spec) Manually specify a room version string (ignored from
+	/// unprivileged users/clients).
+	json::property<name::room_version, json::string>
 >
 {
 	using super_type::tuple;
diff --git a/include/ircd/m/name.h b/include/ircd/m/name.h
index 44122ecbc..4ec0f91f1 100644
--- a/include/ircd/m/name.h
+++ b/include/ircd/m/name.h
@@ -138,6 +138,7 @@ struct ircd::m::name
 	static constexpr const char *const power_level_content_override {"power_level_content_override"};
 	static constexpr const char *const parent_room_id {"parent_room_id"};
 	static constexpr const char *const creator {"creator"};
+	static constexpr const char *const room_version {"room_version"};
 
 	static constexpr const char *const id_server {"id_server"};
 
diff --git a/ircd/m_name.cc b/ircd/m_name.cc
index c49d8306d..bfb5681d0 100644
--- a/ircd/m_name.cc
+++ b/ircd/m_name.cc
@@ -117,6 +117,7 @@ constexpr const char *const ircd::m::name::guest_can_join;
 constexpr const char *const ircd::m::name::power_level_content_override;
 constexpr const char *const ircd::m::name::parent_room_id;
 constexpr const char *const ircd::m::name::creator;
+constexpr const char *const ircd::m::name::room_version;
 
 constexpr const char *const ircd::m::name::id_server;