Upgrade to v16 : The files of the app "activity" were not correctly replaced

Hello

trying to uprade to v16 and receiving following error :

UnexpectedValueException:
The files of the app “activity” were not correctly replaced before running the update

details are :


sudo -u www-data php /var/www/nextcloud/occ upgrade
Nextcloud or one of the apps require upgrade - only a limited number of commands are available
You may use your browser or the occ upgrade command to do the upgrade
Set log level to debug
Updating database schema
Updated database
UnexpectedValueException: The files of the app “activity” were not correctly replaced before running the update
Update failed
Maintenance mode is kept active
Reset log level

Thanks for any help.