This is a pretty simple script which just polls the DCS Updates page (https://updates.digitalcombatsimulator.com) periodically and compares the latest version on that page with the version listed in your game's autoupdate.cfg file.
If they do not match it will ding the terminal and optional post a message to a Discord webhook URL and then exit. Otherwise it will keep checking every few minutes (configurable).
Rename "config.ini.example" to "config.ini" and then fill it out as instructed inside the file. Use your favorite text editor.
You will need Perl and Cpanminus installed. Run cpanm --installdeps . to install this script's dependencies, and then perl update-check.pl to start the script.
Just double click the .exe file after filling out the config.
Either create a config file called "windows.ini" or edit Makefile to use your config.ini instead for Windows.
cpanm --installdeps .
cpanm pp
makeMIT