It surprises me that work is still going on on a supposedly vulnerable platform: 1.9.1.x. Is B2dot4 safe for daily use? Is it just a development version leading to a more solid and reassuring future? Is it suitable for normal use without courting disaster?
I put together beta 2.4 version. I picked that one over the KM 1.7 because the history worked. It has slightly newer version Gecko engine than the original KM 1.6 beta version. I am not a coder. I just put together pieces which were made available to me by others. The privacy DLL was recompiled and works better than the original. I was told the actual code did not change.
You are right that the engine is well past its end of cycle time. Mozilla does not any longer produce a Microsoft Foundation Class version of their Gecko engine. Unless we can find a coder who can make a MFC version of a current Gecko engine, I do not see any way forward.