Just upgraded from 2.5.5 to 2.7 Not a smooth upgrade as it whitescreened - when I turned errors on it gave me this:
Fatal error: Class PT_Fieldtype contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (EE_Fieldtype::display_field) in /home/foobar/public_html/foobar/system/expressionengine/third_party/pt_field_pack/pt_fieldtype.php on line 148
Yes it was still running the old field pack but by then I'd not upgraded any third party modules yet.
I'm still running PHP 5.2.15 incase that matters here. Clues?
edit: I've just rolled back to 2.5.5 (and 2.7 failed again) but I can report that my P&T fieldtypes are 1.0.3