Upgraded to 21.04 and now software (ODADrawingsExplorer) is broken

[Robert Heller]

I just upgraded my 20.10 VM to 21.04, and now ODADrawingsExplorer won't 
install:

ub202164:~> sudo apt install ./ODADrawingsExplorer_QT5_lnxX64_7.2dll_22.6.deb
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Note, selecting 'odadrawingsexplorer' instead of './ODADrawingsExplorer_QT5_lnxX64_7.2dll_22.6.deb'
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 odadrawingsexplorer : PreDepends: qt5-default (>= 5.3.0) but it is not installable
E: Unable to correct problems, you have held broken packages.
ub202164:~> sudo apt install qt5-default
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Package qt5-default is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'qt5-default' has no installation candidate

Fortunately, I made a backup, so I can revert to 20.10 and just never update 
it, despite its EOL on July 22, but is that my only option?


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