"database table is locked" when upgrading from 1.8.37 to 1.8.38

[geeky_kappa]

I am running a Debian 12 stable server with PHP 8 & sqlite from offical software source.
Upgraded by full file overwrite, get an error like this:

I have disabled all plugins before upgrade and tried fuser and pragma integrity_check, still no idea how it was locked.
Rollback to 1.8.37 worked, but I still want to know how

[Crazycat]

Did you turn your forum off before running the upgrade ?

[geeky_kappa]

Did you turn your forum off before running the upgrade ?

Not working
My forum has been forgotten so it won't have accidentally access too

[bv64]

did you read this?
https://www2.sqlite.org/cvstrac/wiki?p=DatabaseIsLocked

[Mostafa.Shiraali]

if you not found free solution , I am here for non-free support, if you like you can send message to me through below ways :

Telegram : @MostafaShiraali
Discord : MostafaShiraali#7754(mostafashiraali)

[geeky_kappa]

did you read this?
https://www2.sqlite.org/cvstrac/wiki?p=DatabaseIsLocked

Couldn't find what's accessing the database

[bv64]

it should show you that this is a typical SQLite problem
SQLite is supported, but not recommended for use with MyBB

https://docs.mybb.com/1.8/install/requirements/

[geeky_kappa]

Update: I tried to setup mysql, but triggered OOM killer in migration (my server only has 1GB ram).
Migration to 1.8.38 running on sqlite3 also failed, same database locked error.