Downgrading icingaweb2 to 2.9.6-1 breaks installation

[R-Sommer]

Describe the bug

Downgrading icingaweb2 to 2.9.6-1 breaks installation:

To Reproduce

1. upgrade packages e.g. 2.10.*
2. downgrade packages to e.g. 2.9.6-1.bionic

Expected behavior

Fully functional

Screenshots

Dashboard:

System/Health:

Director is still working, tough:

Your Environment

Include as many relevant details about the environment you experienced the problem in

• Icinga Web 2 version and modules (System - About): 2.9.6
• Web browser used: Chrome Version 99.0.4844.82 (Official Build) (64-bit)
• Icinga 2 version used (icinga2 --version): r2.13.2-1
• PHP version used (php --version): PHP 7.2.24-0ubuntu0.18.04.11
• Server operating system and version: Ubuntu LTS 18.04 and Debian 11 Bullseye

Additional context

• Upgrading from 2.9.5 to 2.9.6 cause identical error (just did some basic tests, tough)
• Upgrading to 2.10.0-2 does not solve this issue

[R-Sommer]

Ok, found the root cause: icingaweb2-module-monitoring got uninstalled and could easily be fixed e.g. with apt install icingaweb2-module-monitoring=2.9.6-1.bionic.

It is obviously caused by the DEB package control since it recommends icingaweb2-module-monitoring without version (same belongs to icingacli).