Issues with migrating configuration from LCNC 2.8.3 buster to 2.9.3 bookworm

Hi,
I have a working configuration on LCNC 2.8.3 running on Buster. I would like to modernize so I'm trying to move to 2.9.3 bookworm. I figured I could just copy my existing configuration and run it, but that throws errors.
My configuration inserts a QtVCP window as additional tab in the Axis UI. Works great on 2.8.3. Now when I run that config on 2.9.3 I get two errors in separate windows. The first window is a QtVCP error window with the message:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/qtvcp/widgets/tab_widget.py", line 43, in tabSizeHint
    return QSize(size.width(), w)
           ^^^^^^^^^^^^^^^^^^^^^^
TypeError: arguments did not match any overloaded call:
  QSize(): too many arguments
  QSize(w: int, h: int): argument 2 has unexpected type 'float'
  QSize(a0: QSize): argument 1 has unexpected type 'int'

The second window is the LinuxCNC log (attached as file), where the problem line seems to be:

[QTvcp.QTVCP.WIDGETS.SCREEN_OPTIONS][[36mINFO[0m]  [32mInstalling Embedded tab:BaxEDM, default, halcmd loadusr -Wn qtvcp_embed qtvcp -d -c qtvcp_embed -x {XID} baxedm2[0m (screen_options.py:461)
[QTvcp.QTVCP.WIDGETS.SCREEN_OPTIONS][[33mWARNING[0m]  problem inserting VCP 'BaxEDM' to location: rightTab :
 'VCPWindow' object has no attribute 'rightTab' (screen_options.py:485)

Any ideas how to resolve this?

I installed the PyQt dev tools on this new 2.9.3 + bookworm PC and tried to open the *.ui file with the PyQt designer tool. It threw the same error. I can open this same ui file on my 2.8.3 + buster PC without any problems.
So something has changed in the toolchain that cannot deal with my "old" ui file.

In retrospect I should have started this tread in the PyQt section, but I cannot move it. If you are an admin, can you move it for me?

There is no PyQT section, do you mean QTVCP or QTPyVCP?

QTPyVCP would be the best match.

Moved, thank you.

I fixed it, but probably not in the easiest way. I completely rebuild my *.ui file with the designer, but used the designer on the new pc instead. Screens look the same, use the same widgets and now the UI runs.
Loading a *.ui made on a older version apparently is not backwards compatible...

After the ui finally loaded I ran into other issues. Took me a while to find what was causing that. Turned out my existing python user scripts refused to run. To fix that the first line in the *.py files needed to be changed from:
#!/usr/bin/env python
to
#!/usr/bin/env python3
also I changed the rights to the python files with chmod u+x

After that the scripts ran without any problems.