I have installed on a Debian 10 server with Apache2 and PHP 7.3.19 in addition to the 19.0.2 version of Nextcloud.
This tells me that there is already a new version to upgrade (19.0.3) and that all APPs have an updated version that supports the upgrade.
When I access the update application and click on the update button, it displays the following error:
“Check expected files
The following additional files have been found:
and does not allow the nextcloud version to be updated.
Thank you very much for your help