Hey! Version 2.5.3 of amavisd-new was released 12-Dec-2007. It compiles and installs with no changes to the ebuild apart from renaming. I haven't run into any backward-incompatible changes to the config files: I upgraded directly to this version from the latest marked stable version (2.4.1) with no problems. Thanks Jason
I've tested upgrades and fresh installs on amd64 and x86 with no issues. I recommend stabilizing on this latest version 2.5.3.
2.5.3 in the tree now. Sorry for the delay, it's christmas and everything...