I have Snagit 2020 deployed in German with the MSI installer provided by Tecchsmith.
In the applicability rules, there is this line " Key="HKEY_LOCAL_MACHINE" Subkey="SOFTWARE\TechSmith\SnagIt\20" Value="ApplicationLanguage" Comparison="EqualTo" Data="ENU" />"
In my case this value is "DEU" on my Windows client, so the update is not showing up in the software center.
Installed in English language, the update applies but then I'm unable to uninstall the application, it reports error code 350 (https://support.techsmith.com/hc/en-us/articles/360018899472-Snagit-Windows-Error-Code-350-An-Unknown-Error-Occurred)
Do you know if the same installer can update German and English installations?
I just tried it on a new and clean machine and watching with process explorer what's happening in the background. Snagit 20.0.1 installed by MSI with the license key and language german via SCCM, then updating it with snagit.exe (20.0.2) from command line with the parameter /s worked fine. I tried the same with the MSI 20.0.1 and english language and then updating it with the in SCCM published update from you and this worked fine too. And this time the uninstall didn't show the error code 350. So I think, yes, the same installer can update both languages.