..for a rather strange reason like
>>> md5 src_uri ;-) postfix-2.2.5.tar.gz
mind the following:
* You are upgrading from a incompatible version.
* You MUST stop postfix BEFORE install it to your system.
* If you want a minimal downtime, emerge postfix with:
* `FORCE_UPGRADE=1 emerge –buildpkgonly postfix`; then
* `/etc/init.d/postfix stop && emerge –usepkgonly postfix`
* run etc-update or dispatch-conf and merge the configuration files.
* Next /etc/init.d/postfix start