AttributeError: 'NoneType' object has no attribute 'version' in checkAPT.py

[KingOfPlayer]

Describe the bug
The Update Manager is unable to update the version list. The process fails when it encounters a package that is installed but lacks a "candidate" version. In my case, the "snapd" package caused this error, preventing any other updates from being displayed.

Screenshots

To Reproduce
I'm not sure how it happened. At one point I was enabling and deactivating the "snap" package.

Expected behavior
The Update Manager should handle packages without a candidate version gracefully and continue refreshing the rest of the list.

Distribution:

• Linux Mint
• LMDE
• Other (please specify)

Software version:
7.1.1

Logs:

2026.04.30@21:54 ++ Launching Update Manager
2026.04.30@21:54 ++ Initial refresh will happen in 0 day(s), 0 hour(s) and 10 minute(s)
2026.04.30@21:54 ++ Inhibited power management
2026.04.30@21:54 ++ Checking for updates
2026.04.30@21:54 -- Error in checkAPT.py, could not refresh the list of updates
2026.04.30@21:54 ++ Resumed power management

Additional context
There is terminal log

<class 'AttributeError'>
Error in checkAPT: 'NoneType' object has no attribute 'version'
Traceback (most recent call last):
  File "/usr/lib/linuxmint/mintUpdate/mintUpdate.py", line 2227, in check_apt_in_external_process
    check.find_changes()
  File "/usr/lib/linuxmint/mintUpdate/checkAPT.py", line 63, in find_changes
    if (pkg.is_installed and pkg.candidate.version != pkg.installed.version):
                             ^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'version'

Adding a null check for the candidate object would solve this