I started having troubles installing Tera Term on my corporate laptop running Windows 10 Enterprise. Windows Defender sees that the publisher of the application is unknown, i.e. installation file does not contain Code Signing Certificate, and deletes .exe file before I can execute it. Since majority of Tera Term users run it on work PCs, I am most likely not the only one having such issue.
I used Code Signing Certificate couple of years ago when releasing the last versions of LogMeTT and TTLEditor. It cost me about 100$ per year. The price may be lower now, but unfortunately we are approaching the time when freeware development will require more than only personal time investment.