diff --git a/src/ejabberd_auth.erl b/src/ejabberd_auth.erl
index 7894679a5..b11bfe3c8 100644
--- a/src/ejabberd_auth.erl
+++ b/src/ejabberd_auth.erl
@@ -139,7 +139,7 @@ handle_cast(config_reloaded, #state{host_modules = HostModules} = State) ->
 		  NewModules = auth_modules(Host),
 		  start(Host, NewModules -- OldModules),
 		  stop(Host, OldModules -- NewModules),
-		  reload(Host, lists_intersection(OldModules, NewModules)),
+		  reload(Host, misc:intersection(OldModules, NewModules)),
 		  maps:put(Host, NewModules, Acc)
 	  end, HostModules, ejabberd_config:get_myhosts()),
     init_cache(NewHostModules),
@@ -834,12 +834,6 @@ validate_credentials(User, Server, Password) ->
 	    end
     end.
 
-lists_intersection(L1, L2) ->
-    lists:filter(
-      fun(E) ->
-              lists:member(E, L2)
-      end, L1).
-
 import_info() ->
     [{<<"users">>, 3}].
 
diff --git a/src/misc.erl b/src/misc.erl
index 2e1b3f008..69534ef33 100644
--- a/src/misc.erl
+++ b/src/misc.erl
@@ -35,7 +35,7 @@
 	 now_to_usec/1, usec_to_now/1, encode_pid/1, decode_pid/2,
 	 compile_exprs/2, join_atoms/2, try_read_file/1, get_descr/2,
 	 css_dir/0, img_dir/0, js_dir/0, msgs_dir/0, sql_dir/0,
-	 read_css/1, read_img/1, read_js/1, try_url/1]).
+	 read_css/1, read_img/1, read_js/1, try_url/1, intersection/2]).
 
 %% Deprecated functions
 -export([decode_base64/1, encode_base64/1]).
@@ -280,6 +280,13 @@ get_descr(Lang, Text) ->
     Copyright = ejabberd_config:get_copyright(),
     <<Desc/binary, $\n, Copyright/binary>>.
 
+-spec intersection(list(), list()) -> list().
+intersection(L1, L2) ->
+    lists:filter(
+      fun(E) ->
+              lists:member(E, L2)
+      end, L1).
+
 %%%===================================================================
 %%% Internal functions
 %%%===================================================================
diff --git a/src/mod_muc.erl b/src/mod_muc.erl
index f44b53927..d7bb194c1 100644
--- a/src/mod_muc.erl
+++ b/src/mod_muc.erl
@@ -295,6 +295,15 @@ handle_cast({reload, ServerHost, NewOpts, OldOpts}, #state{hosts = OldHosts}) ->
 	      ejabberd_router:unregister_route(OldHost),
 	      unregister_iq_handlers(OldHost)
       end, OldHosts -- NewHosts),
+    lists:foreach(
+      fun(Host) ->
+	      lists:foreach(
+		fun({_, _, Pid}) when node(Pid) == node() ->
+			Pid ! config_reloaded;
+		   (_) ->
+			ok
+		end, get_online_rooms(ServerHost, Host))
+      end, misc:intersection(NewHosts, OldHosts)),
     {noreply, NewState};
 handle_cast(Msg, State) ->
     ?WARNING_MSG("unexpected cast: ~p", [Msg]),
diff --git a/src/mod_muc_room.erl b/src/mod_muc_room.erl
index 3ff241929..f1acf3cb0 100644
--- a/src/mod_muc_room.erl
+++ b/src/mod_muc_room.erl
@@ -678,6 +678,19 @@ handle_info({iq_reply, timeout, IQ}, StateName, StateData) ->
     Err = xmpp:err_recipient_unavailable(Txt, IQ#iq.lang),
     ejabberd_router:route_error(IQ, Err),
     {next_state, StateName, StateData};
+handle_info(config_reloaded, StateName, StateData) ->
+    Max = gen_mod:get_module_opt(StateData#state.server_host,
+				 mod_muc, history_size),
+    History1 = StateData#state.history,
+    Q1 = History1#lqueue.queue,
+    Q2 = case p1_queue:len(Q1) of
+	     Len when Len > Max ->
+		 lqueue_cut(Q1, Len-Max);
+	     _ ->
+		 Q1
+	 end,
+    History2 = History1#lqueue{queue = Q2, max = Max},
+    {next_state, StateName, StateData#state{history = History2}};
 handle_info(_Info, StateName, StateData) ->
     {next_state, StateName, StateData}.