Nextcloud 15 does not recognize updated PHP

I updated to Nextcloud 15 and received several error messages in the settings overview. I was able to resolve all instead of the last one:

German: Du verwendest derzeit PHP 7.0.33-1+0~20181208203126.8+stretch~1.gbp2ff763
Englisch: You are using PHP 7.0.33-1+0~20181208203126.8+stretch~1.gbp2ff763

I upgraded my system (debian stretch) to PHP 7.2

# php --version
PHP 7.2.13-1+0~20181207100540.13+stretch~1.gbpf57305 (cli) (built: Dec  7 2018 10:05:40) ( NTS )

But I still get this error message in Nextcloud. Does Nextcloud not recognize my updated PHP version? Is the old PHP version still existing and do I need to remove? Or do I change any config file?

Nextcloud version 15.0.0
Debian Strech

Issue resolved, I needed to activate PHP7,2 for the apache2 server

a2enconf php7.2