Impossible to install on current Tuxedo OS (based on Kubuntu)

[dmatej]

Both using the script or apt:

The following packages have unmet dependencies:
 libqt6printsupport6 : Breaks: libqt6printsupport6t64 (< 6.9.2+dfsg-3ubuntu1~tux1) but 6.8.2+dfsg-8~tux1 is to be installed
 qdigidoc4 : Depends: libqt6network6t64 (>= 6.4.0) but it is not installable
             Depends: libqt6widgets6t64 (>= 6.2.0) but it is not installable
 web-eid-native : Depends: libqt6network6t64 (>= 6.1.2) but it is not installable
                  Depends: libqt6widgets6t64 (>= 6.1.2) but it is not installable
E: Unable to correct problems, you have held broken packages.

lsb_release -a
No LSB modules are available.
Distributor ID: Tuxedo
Description:    TUXEDO OS
Release:        24.04
Codename:       noble

Claude AI says:

Root cause: The t64 suffix packages are the 64-bit time transition variants introduced in Ubuntu 24.04. Mixing a repo that's moved to Qt 6.9 with one still on Qt 6.8 will cause these breaks. The cleanest fix is to ensure all Qt6 packages come from the same repository at the same version.

So I guess it is a breaking change between Qt6.8 and Qt6.9 and you should adapt your dependencies. Am I right?

DigiDoc4 (from the tux1 PPA or Estonian ID-software repo) was built against Qt 6.8
Your system (likely Ubuntu 24.10 or 25.04) has moved to Qt 6.9
The 6.9 packages introduce a Breaks: constraint that explicitly rejects the older t64 variants that DigiDoc4 depends on

[dmatej]

Seems it is enough just to recompile the project with Qt6.9 and it works again. Same applies to the web-eid project.