I've just now upgraded from 5.6.18 to 5.6.20, on my Windows 10 Desktop PC. I'm about to run IMatch in a minute for the first time since upgrading. This thread is because I was told during the installation process that I would have to reboot after completion of installation for changes to take effect, and I want to know why that be the case. Thanks!
Short answer: Mario updated some of the 'behind the scenes' components used in IMatch (to support various fixes and future capabilities). They require updating some files via a restart. Not too unusual these days for various programs.
IMatch 5.6.20 ships with the most recent version of the Microsoft runtime components. These cannot be updated while in use, and many programs use these components. In that case Windows installer prompts for a reboot. Nothing unusual.