Hi - With some trepidation I tried upgrade from 5.5 to 6.01custom and seems to have worked a treat except for the known webmail bug - had to change the horde DbPassword - and ipsec looks like it will need reinstall. Clam and spamassassin both carried on working which was very pleasing, as have most of my other contribs as far as I can see.
Regards
Brian Kirk