Godot 4.0 has heavy changes, projects are not compatible.
I found that deb package.
https://packages.debian.org/sid/godot3
But I wonder if this is a stable version.
A 3.6 stable version exists.
https://github.com/godotengine/godot/tree/3.6-stable
Thank you for reading.
Request an update for Godot 3 branch [Solved]
Re: Request an update for Godot 3 branch
The Sid 3.6 is the stable version--I'll look at it later tonight.
MXPI = MX Package Installer
QSI = Quick System Info from menu
The MX Test repository is mostly backports; not the same as Debian testing
QSI = Quick System Info from menu
The MX Test repository is mostly backports; not the same as Debian testing
Re: Request an update for Godot 3 branch [Solved]
We now have a backport of 3.6 in the MX 23 test repo.
MXPI = MX Package Installer
QSI = Quick System Info from menu
The MX Test repository is mostly backports; not the same as Debian testing
QSI = Quick System Info from menu
The MX Test repository is mostly backports; not the same as Debian testing
Re: Request an update for Godot 3 branch
Thank you. MX has a great community 

Re: Request an update for Godot 3 branch
Let us us know how it's working, so it can get moved to main.
MXPI = MX Package Installer
QSI = Quick System Info from menu
The MX Test repository is mostly backports; not the same as Debian testing
QSI = Quick System Info from menu
The MX Test repository is mostly backports; not the same as Debian testing
Re: Request an update for Godot 3 branch
This version runs, but an object position has changed comparing to the 3.5 version.
In order to catch the bug, I spent hours trying to reproduce the behaviour on a new scene without success.
Its the same on a Godot 3.6 executable directly downloaded from the Godot repo, so its not a problem from the package IMO.