What type of hardware are you using: Old laptop or computer
What YunoHost version are you running: YunoHost 12.0.14 (stable).
What app is this about: Nextcloud
Describe your issue
Hello,
I try in English 
I have my own YunoHost since 2020. Updated et upgraded regulary.
(Thanks a lot for this project. I’m a good “salesman” with YunoHost and Nextcloud toward my friends 
)
I have upgraded my YunoHost to 12.0.14 with success (but this upgrade is recent).
Update and upgrade OK for all except Nextcloud.
I have 2 Nextcloud into this YunoHost and the issue is similar.
Update failed and Nextcloud is broken:
“Your data directory is invalid.
Make sure that the data directory contains an ‘.ocdata’ file at its root.”
I have to remove the App and restore with my Backup.
Remove and restore is a good way to have a functional Nextcloud
But it’s not a solution and I’m blocked in my current version.
Maybe the issue is my bad because I want upgrade Nextcloud 29.0.10 to
31.0.4…
Into the logs I can see “An error occurred inside the app upgrade script”.
Here is the last logs (I retried today).
Thank for all idea
Best
NB : I have another Yunohost on a VPS and no issue but I think it was an upgrade from NC29 to NC30 (not sure)