Compatibility of Proof General
==============================

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

 Emacs 22.1.1	       -- recommended and supported

 Emacs 21.4.1          -- tested; poorer X-Symbol sub/superscript support
 XEmacs 21.5 (beta28)  -- tested; PG has workarounds for several bugs
 XEmacs 21.4.XX	       -- tested

and prover versions:

 Coq 8.1
 Isabelle2005
 Isabelle2007

Maintaining compatibility across proof assistant versions, Emacs
versions and operating systems is a big challenge!  Please visit this
wiki page to check on others experience and report your own:

 http://proofgeneral.inf.ed.ac.uk/wiki/Main/PGEmacsCompatibility  

Unfortunately it's too difficult to maintain backward compatibility.
Some old version compatibility has been removed here, specifically
affecting:

 Coq 7
 Isabelle 2004
 Earlier buggy versions of GNU Emacs 21