Changes since the last release may be found by performing a "cvs log" command on the file stamp.c.
(just to scripting)
Sergey Malkin from MicroSoft tells me:
Each shaping engine in Uniscribe can decide on its requirements for layout tables - some of them require both GSUB and GPOS, in some cases any table present is enough, or it can work without any table.Sometimes, purpose of the check is to determine if font is supporting particular script - if required tables are not there font is just rejected by this shaping engine. Sometimes, shaping engine can not just reject the font because there are fonts using older shaping technologies we still have to support, so it uses some logic when to fallback to legacy layout code.
In your case this is Hebrew, where both tables are required to use OpenType processing. Arabic requires both tables too, Latin requires GSUB to execute GPOS. But in general, if you have both tables you should be safe with any script to get fully featured OpenType shaping.
So the script sub-table of both GPOS/GSUB should contain all scripts used in either (rather than just the scripts used in the current one).
(Behavior in the outline view when there is a selection remains the same. So if the endpoints of a spline are both selected then all local extrema will be added to that spline, no matter how long it may be).