diff --git a/FHEM/10_KNX.pm b/FHEM/10_KNX.pm
index 8f8364546..e567c14a2 100644
--- a/FHEM/10_KNX.pm
+++ b/FHEM/10_KNX.pm
@@ -75,6 +75,7 @@
 #              new dpt7.600, dpt9.029,dpt9.030  
 # MH  20210818 E04.67 1st checkin SVN version
 #              docu correction
+# MH  20210829 fix crash when using Attr KNX_toogle (related to package)
 
 
 #04.65 package main;
@@ -112,7 +113,7 @@ BEGIN {
           readingFnAttributes
           InternalTimer RemoveInternalTimer
           init_done
-          IsDisabled IsDummy
+          IsDisabled IsDummy IsDevice
           deviceEvents devspec2array
           AnalyzePerlCommand EvalSpecials
           fhemTimeLocal)