Interesting conundrum: We've recently moved a project to LetsEncrypt and now between 1-2% of our users can't use our product anymore. (Because of the missing root cert on their ancient OS)

On one hand I can totally understand why people are using old hard- and software, with Money being the main reason - On the other hand, yo, you're using an unmaintained, inherently insecure operating system to use the interwebs. STAHP, forcrissakes, STAHP.