> ... as the frigging IO::Socket::SSL.pm bug

This is not a bug in IO::Socket::SSL but a failure in Net::SMTP::TLS to properly set SSL_version. Note that the module you use had its last release 9 years ago and is clearly unmaintained. This problem is fixed in Net::SMTP::TLS::ButMaintained (last release two years ago) but I recommend to actually use current releases of Net::SMTP (version 3.x) which have TLS and IPv6 support built in.

And please, if you think there is an unfixed bug in a module file a bug report instead of unhelpfully complaining about the "frigging" module. The author of the module might actually be willing to help you. In this case the relevant bug report was already filed 2012 and if you would care to read it you would see the problem explained and also described what need to be fixed.

Steffen Ullrich, maintainer of IO::Socket::SSL