Support intro
Sorry to hear you’re facing problems 
help.nextcloud.com is for home/non-enterprise users. If you’re running a business, paid support can be accessed via portal.nextcloud.com where we can ensure your business keeps running smoothly.
In order to help you as quickly as possible, before clicking Create Topic please provide as much of the below as you can. Feel free to use a pastebin service for logs, otherwise either indent short log examples with four spaces:
example
Or for longer, use three backticks above and below the code snippet:
longer
example
here
Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version (eg, 20.0.5): 28.0.0
Operating system and version (eg, Ubuntu 20.04): Debian GNU/Linux 11 (bullseye) Kernel: Linux 5.10.0-25-amd64
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.56
PHP version (eg, 7.4): 8.2.13
The issue you are facing:
After updating from 27.1.5 RC1 to 28.0.0 RC4 (with interim updates in between), I’ve noticed several issues, but I’m not sure how/where to report them.
========
ISSUE #1:
In prep for the upgrade, the updater informs of certain “incompatible” apps, which will be disabled. However, AFTER the upgrade, it lists MORE incompatible applications than it did prior to the upgrade – AND some of those were previously said to be ‘compatible’ with the newer version.
PRIOR TO running the web updater, it says:
Version
Nextcloud Hub 6 (27.1.4 RC1)
Update
A new version is available: Nextcloud 28.0.0 RC1
5 apps have no compatible version for this Nextcloud version available.
Apps missing compatible version
Draw.io ↗
Music ↗
ONLYOFFICE ↗
Preview Generator ↗
Quick notes ↗
Apps with compatible version
Calendar ↗
Contacts ↗
Group folders ↗
Mail ↗
Notes ↗
Passwords ↗
Nextcloud Office ↗
Collabora Online - Built-in CODE Server ↗
Talk ↗
Tasks ↗
-----------
However, AFTER the upgrade, it says:
These incompatible apps will be disabled:
Draw.io (drawio)
files_rightclick (files_rightclick)
Group folders (groupfolders)
Music (music)
ONLYOFFICE (onlyoffice)
Preview Generator (previewgenerator)
Quick notes (quicknotes)
Nextcloud Office (richdocuments)
Talk (spreed)
---------------------------
You can see several inconsistencies between the “before” list and the “after” list. This needs to be corrected, as it could mislead some regarding the loss of certain apps.
========
ISSUE #2:
After the upgrade, even though “OnlyOffice” was supposed to have been disabled due to incompatibility, it was STILL enabled, resulting in a multitude of error messages in the logs. I had to manually disable OnlyOffice to stop these messages.
Typical messages said: “Could not boot onlyoffice: Could not resolve eventDispatcher! Class "eventDispatcher" does not exist”
The updater did NOT disable this app (and perhaps others) that were incompatible.
========
ISSUE #3:
When checking the results of the upgrade in the web interface (“Administration settings–>Overview”), due to the many errors mentioned in ISSUE #2 above, it suggests checking the “installation guides” for advice on how to fix the issues. But the link provided on that screen is now DEAD.
Specifically, the link for the “installation guides” on that page is a DEAD link. The underlying link is:
https://docs.nextcloud.com/server/28/go.php?to=admin-install
I believe this occurred when upgrading from 27.1.5 → 28.0.0 (RC 1 or 2). I’m on RC4 now, but I believe it was present even before RC4.
=========
I’m on the ‘beta’ channel, so I realize these possibilities are to be expected – I’m just not sure how to report them. They seem to be genuine bugs, not issues specific to my installation.