*** The mail-fetching functions have changed. See the manual for the
many details. In particular, all procmail fetching variables are gone.
+If you used procmail like in
+
+(setq nnmail-use-procmail t)
+(setq nnmail-spool-file 'procmail)
+(setq nnmail-procmail-directory "~/mail/incoming/")
+(setq nnmail-procmail-suffix "\\.in")
+
+this now has changed to
+
+(setq mail-sources
+ '((directory :path "~/mail/incoming/"
+ :suffix ".in")))
+
+More information is available in the info doc at Select Methods ->
+Getting Mail -> Mail Sources
+
*** Gnus is now a MIME-capable reader. This affects many parts of
Gnus, and adds a slew of new commands. See the manual for details.