Nope. As Sock said in the Func_ thread, there are too many changes between 1.42 and 1.5 for a patch-only release. Also, for the same reason you won't be able to use your savegames from 1.42 in 1.5...
♪ I'm skiiiiiiinnin' in the pain, just skiiiiiiinnin' in the pain ♪
♪ What a glorious feelin' I'm haaaaaaappy again ♪