diff --git a/fhem/FHEM/00_MQTT2_CLIENT.pm b/fhem/FHEM/00_MQTT2_CLIENT.pm
index 1a4964d28..ef067c63c 100644
--- a/fhem/FHEM/00_MQTT2_CLIENT.pm
+++ b/fhem/FHEM/00_MQTT2_CLIENT.pm
@@ -12,6 +12,7 @@ sub MQTT2_CLIENT_Undef($@);
 sub MQTT2_CLIENT_doPublish($@);
 sub MQTT2_CLIENT_Disco($;$$);
 
+use vars qw($FW_chash);   # client fhem hash
 use vars qw(%FW_id2inform);
 
 # See also:
diff --git a/fhem/FHEM/00_MQTT2_SERVER.pm b/fhem/FHEM/00_MQTT2_SERVER.pm
index c12a7bb3f..8b101b990 100644
--- a/fhem/FHEM/00_MQTT2_SERVER.pm
+++ b/fhem/FHEM/00_MQTT2_SERVER.pm
@@ -12,6 +12,7 @@ sub MQTT2_SERVER_Write($$$);
 sub MQTT2_SERVER_Undef($@);
 sub MQTT2_SERVER_doPublish($$$$;$);
 
+use vars qw($FW_chash);   # client fhem hash
 use vars qw(%FW_id2inform);
 
 # See also: