Kerio 2 is still available and free (but no updates) Kerio (now sunbelt) does revert to a free version (certain functions are disabled), updates to that?
Last time I checked the Kerio series was not getting any updates, 2.x code taken over from Tiny by a group calling themselves Kerio. They didn't do much to 2.x, but abandon it, 3.x was a failure in beta, 4.x was released as full version when they didn't fix all the major beta bugs first which caused massive negative pr. Kerio eventually sold/whatever it to sunbelt who also has not updated it in a while... Everything after 2.x was a constant failure, 2.x was just not user friendly as all of these newer security suites, you actually had to know what you were doing, even the help file was next to useless for anything advanced.
The early Kerio 4s weren't perfect. Sunbelt/Kerio 4.5 isn't perfect. But somewhere in between you have Kerio 4.2 and Sunbelt/Kerio 4.3. Could be light and user friendly alternatives to the modern bloatware. Not much support, of course, but you don't need support for a firewall that works. The documentation was OK.
Unfortunatelly I didn't find a single version after 4.0 which doesn't have one or more problems. BSOD is the most annoying one, but there are others, like changing the order of the rules by the firewall... 2.1.5 was probably the best firewall (in the classic way, without HIPS features) ever.
I had those same problems. Sooner or later, the BSOD usually arrived. Version 4.2.2 ran best for me, but even that one logged incorrectly, and frequently ignored custom packet filter rules.
