I have one nextcloud server in local network with openSuSE Tumbleweed. Because openSuSE Leap 16.0 release is current classic release, so I changed repositories to openSuSE Leap 16.0 by YaST.

https://download.opensuse.org/distribution/leap/16.0/repo/non-oss/
https://download.opensuse.org/distribution/leap/16.0/repo/oss/

And run zypper dup upgrade to openSuSE Leap 16.0.

After finished and reboot, the kernel should manual changed by YaST. Otherwise maybe fail when boot.

After switch to openSuSE Leap 16.0, the nextcloud server stopped with http code 500. The message show in browser is:

Internal Server Error

The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the server log.

I searched the apache and nextcloud log. There is no useful information. And google information is no helpful. I don't know how to solve the problem. And the config.php file is no changed. So I only install new instance for check which one problem: environment or config.php file.

The installed clean nextcloud server instance run success. So I check two config.php file, final I find remove the lines like below can solve the problem:

  'memcache.local' => '\\OC\\Memcache\\APCu',
  'memcache.locking' => '\\OC\\Memcache\\Redis',

So I check installed package in openSuSE Leap 16.0. I find there are no php8-APCu/php8-redis in the release. And the redis is removed. My nextcloud server only for my personal use. So I remove the elder config.php memcache option. The nextcloud server run success.