Mint upgrade and dt

I’ve so far only ran dt v. 4.2.1 because it’s the latest version that Linux Mint’s Program Manager offer in my current LM version 20.3.

I was now intending to upgrade to later LM 21 versions, but as part of this process the LM Upgrade Tool then informs me:
image
Why I’m told 3.0.1 is the official version, as PM has offered 4.2.1 for quite some time, is beyond me.
Does anybody else understand why this comes up?

(EDIT: I’m aware of the possibility to run newer versions of dt as flatpak … )

when upgrading mint it’ll ask to remove any additional sources and thus any packages coming from external repositories as the upgrade manager does not check for the up-gradability of packages not in official mint repositories.

Once you have upgraded you can re add these external sources (if still compatible) and re install these packages.

Thanks, I’m aware of that.
I was wondering where the dt. v. 3.0.1 is coming from, because I believe Mint distro was long past that version in the official repos.

from a very quick search, if you’re upgrading from 20.3 DT version should be 3.8.1-2 in deed but if you’re starting from version 20.0 then your current DT version is darktable(3.0.1-0ubuntu1)

(mint 20.0 → ubuntu focal )
Ubuntu focal package list ‘graphics’ section → Ubuntu – Software Packages in "focal", Subsection graphics

OK. Thanks for the clarification!