I have made extensive test on UCS 5 and UCS-5 looks ready for prod, at least for new installations. but … I am a bit surprised to see an upgrade proposition in my ucs-4 servers, because UCS-5 is absolutely not ready to replace existing UCS-4 regarding app availability.
Or should you noisily alert all UCS upgrade about compatibility in the app center, or regarding installed app in previous UCS-4.
Some essential APP have comme later like NextCloud, but there is essential app like Nagios, Kopano, openExchange,
I have made a diff regarding app availability between ucs4 and ucs5 and I feel scary by the lost of all these app:
even in dev-test-mode lots are not installable. impossible for me to install letsencrypt for instance. So I am really not sure if installed UCS-4 server are ready to migrate with this lack of apps.
Could you please provide clear instruction on what are optimal conditions for migrating UCS-4 to UCS-5