[TYPO3-calendar] TYPO3 v9: cal 2.0: Error messages "Parameter must be an array..."

[Markus]

Hi,

I have just upgraded from TYPO3 v8.7 to 9.5 and from cal 1.xx to cal 2.0

The TYPO3 log is flooded with an error message regarding cal extension:

Core: Error handler (FE): PHP Warning: count(): Parameter must be an 
array or an object that implements Countable in 
/......./typo3conf/ext/cal/Classes/View/BaseView.php line 2149


Is this a known issue?

Is there still any bugtracker for cal alive?

Thanks,

Markus