This version of Proof General has been tested with Emacs versions:

 Emacs 21.4.1		 -- recommended
 XEmacs 21.4.XX		 -- stable
 XEmacs 21.5 (beta27)    -- potentially troublesome 

and prover versions:

 Isabelle2005
 Isabelle CVS versions up to 04.01.2007.

For more possibilities, please check and contribute here:
  
   http://proofgeneral.inf.ed.ac.uk/wiki/Main/PGEmacsVer37Final