PGP Questions

I seem to remember reading somewhere that using PGP to encrypt a message for multiple recipients (in the same output file) somehow made cryptanalysis easier, but I don't seem to recall the rationale behind that concern. Can somebody comment on that. Also, concerning the PGP 2.3a/2.6/2.6ui controversy, is the only "problem" with 2.6 the fact that after 9/1/94 it will start reporting an incompatible version number that will make its output unreadable by older versions? If so, and if source code is available, why couldn't the date checking routine be located in the source code and simply commented out, then the whole thing recompiled? --