I performed the MT 3.0D > 3.11 upgrade, and all went well, except the mt-upgrade31.cgi gives me the 500 "Premature end of script headers" error. Permissions are 755, I uploaded it as ascii. All the other cgi scripts work fine, except any upgrade one.
Otherwise, 3.11 seems to work fine. The one weird problem is that my although my 3.0 categories work fine, they do not appear in the categories admin (I suspect the upgrade script corrects this?).
Any help is appreciated.