As per Denys comments

src/auth/ejabberd_auth.erl

@@ -363,7 +363,7 @@ remove_user(#jid{luser = LUser, lserver = LServer}) ->
                                        host_type => HostType,
                                        lserver => LServer,
                                        element => undefined }),
-            mongoose_hooks:remove_user(HostType, Acc, LServer, LUser),
+            mongoose_hooks:remove_user(Acc, LServer, LUser),
             ok;
         Error ->
             ?LOG_ERROR(#{what => backend_disallows_user_removal,

src/event_pusher/mod_event_pusher_push_plugin_defaults.erl

@@ -79,7 +79,8 @@ publish_notification(Acc, _, Payload, Services) ->
 
 -spec should_publish(Acc :: mongoose_acc:t(), To :: jid:jid()) -> boolean().
 should_publish(Acc, #jid{} = To) ->
-    try mongoose_users:does_user_exist(Acc, To) of
+    HostType = mongoose_acc:host_type(Acc),
+    try mongoose_users:does_user_exist(HostType, To) of
         false ->
             false;
         true ->

src/inbox/mod_inbox.erl

@@ -300,9 +300,11 @@ maybe_process_message(Acc, Host, From, To, Msg, Dir) ->
                          To :: jid:jid(),
                          Dir :: outgoing | incoming) -> boolean().
 inbox_owner_exists(Acc, From, _To, outgoing) ->
-    mongoose_users:does_user_exist(Acc, From);
+    HostType = mongoose_acc:host_type(Acc),
+    mongoose_users:does_user_exist(HostType, From);
 inbox_owner_exists(Acc, _From, To, incoming) ->
-    mongoose_users:does_user_exist(Acc, To).
+    HostType = mongoose_acc:host_type(Acc),
+    mongoose_users:does_user_exist(HostType, To).
 
 maybe_process_acceptable_message(Host, From, To, Msg, Acc, Dir, one2one) ->
             process_message(Host, From, To, Msg, Acc, Dir, one2one);

src/mam/mod_mam.erl

@@ -281,8 +281,9 @@ filter_packet(drop) ->
     drop;
 filter_packet({From, To = #jid{lserver = LServer}, Acc1, Packet}) ->
     ?LOG_DEBUG(#{what => mam_user_receive_packet, acc => Acc1}),
+    HostType = mongoose_acc:host_type(Acc1),
     {AmpEvent, PacketAfterArchive, Acc3} =
-        case mongoose_users:does_user_exist(Acc1, To) of
+        case mongoose_users:does_user_exist(HostType, To) of
             false ->
                 {mam_failed, Packet, Acc1};
             true ->

src/mongoose_hooks.erl

@@ -27,7 +27,7 @@
          register_command/1,
          register_subhost/2,
          register_user/3,
-         remove_user/4,
+         remove_user/3,
          resend_offline_messages_hook/3,
          rest_user_send_packet/4,
          session_cleanup/5,
@@ -366,13 +366,13 @@ register_user(HostType, LServer, LUser) ->
     ejabberd_hooks:run_for_host_type(register_user, HostType, ok, [LUser, LServer]).
 
 %%% @doc The `remove_user' hook is called when a user is removed.
--spec remove_user(HostType, Acc, LServer, LUser) -> Result when
-    HostType :: mongooseim:host_type(),
+-spec remove_user(Acc, LServer, LUser) -> Result when
     Acc :: mongoose_acc:t(),
     LServer :: jid:lserver(),
     LUser :: jid:luser(),
     Result :: mongoose_acc:t().
-remove_user(HostType, Acc, LServer, LUser) ->
+remove_user(Acc, LServer, LUser) ->
+    HostType = mongoose_acc:host_type(Acc),
     ejabberd_hooks:run_for_host_type(remove_user, HostType, Acc, [LUser, LServer]).
 
 -spec resend_offline_messages_hook(HostType, Acc, JID) -> Result when

src/mongoose_users.erl

@@ -56,9 +56,8 @@ stop_ets(HostType) ->
     Tab = tbl_name(HostType),
     ets:delete(Tab).
 
--spec does_user_exist(Acc :: mongoose_acc:t(), JID :: jid:jid()) -> boolean().
-does_user_exist(Acc, #jid{luser = LUser, lserver = LServer} = JID) ->
-    HostType = mongoose_acc:host_type(Acc),
+-spec does_user_exist(HostType :: mongooseim:host_type(), JID :: jid:jid()) -> boolean().
+does_user_exist(HostType, #jid{luser = LUser, lserver = LServer} = JID) ->
     case does_cached_user_exist(HostType, LServer, LUser) of
         true -> true;
         false ->