This version of Nextcloud is not compatible with > PHP 7.3

thanks thanks
this is how it works now. Regarding nextcloud it takes a little patience until it is shown that the cron has been executed. 2x start the cron manually then it will also be shown in the nextcloud.
thanks from swiss
andreas

I know its an old thread but hopefully the following helps somebody: I had to update a old instance from version 15 to 20. As @bdichgans said I just modify the check in …/nextcloud/lib/versioncheck.php - i just delete die ! in the second if-part.Next step is to save every config and special apps/data, delete the whole directory, copy the next major release in the nextcloud folder, copy back the config and data, do the occ upgrade thing. And go on with the next major release exactly the same until you are at the actual version. It did not make any problems for me upgrading from 15 to 20.