The keys used are:
!: modified feature, -: deleted feature, +: new feature
+hg tip:
+
+ ! $thorough_search defaults to yes
+ + imap-logout-all closes all open IMAP connections
+ ! header/body cache paths are always UTF-8
+ + $wrap_headers to control outgoing message's header length
+ + all text/* parts can be displayed inline without mailcap
+ + send-hooks now run in batch mode; previously only send2-hooks ran.
+
+1.5.20 (2009-06-14):
+
+ ! mbox/mmdf new mail flag is kept when leaving folders with new mail
+ ! $fcc_attach is a quadoption now
+ + $honor_disposition to honor Content-Disposition headers
+ + $search_context specifies number of context lines for search results
+ in pager/page-based menus
+ ! ssl_use_sslv2 defaults to no
+ + uncolor works for header + body objects, too
+ + the "flagged" and "replied" flags are enabled/supported for
+ POP when built with header caching
+ ! browser correctly displays maildir's mtime
+ + <set-flag> and <clear-flag> work in the pager, too
+ + ~x pattern also matches against In-Reply-To
+ + lower case patterns for string searches perform case-insensitive
+ search as regex patterns do (except IMAP)
+ + $ssl_verify_dates controls whether mutt checks the validity period of
+ SSL certificates
+ + $ssl_verify_host controls whether mutt will accept certificates whose
+ host names do not match the host name in the folder URL.
+
1.5.19 (2009-01-05):
+ ! command-line arguments: -a now mandates -- at end of file list
+ support for SSL certificate chains
+ <what-key> function works in pager, too
+ support for tokyocabinet (qdbm successor)