The official Postfix release is called 2.1.x where 2=major release
number, 1=minor release number, x=patchlevel.  Snapshot releases
are now called 2.2-yyyymmdd where yyyymmdd is the release date
(yyyy=year, mm=month, dd=day).  The mail_release_date configuration
parameter contains the release date (both for official release and
snapshot release).  Patches are issued for the official release
and change the patchlevel and the release date. Patches are never
issued for snapshot releases.

Major changes with snapshot Postfix-2.2-20040621
================================================

Control over the working directory when executing an external
command.  With the pipe(8) mailer, specify directory=pathname, and
with local(8) specify "command_execution_directory = expression"
where "expression" is subject to $home etc. macro expansion. The
result of macro expansion is restricted by the set of charaacters
specified with execution_directory_expansion_filter.
