ReActiv 1.6 Update 15 has been released and can be downloaded from the program's updates page http://www.geocentrix.co.uk/reactiv/update
Improvements in this release are:
2062 Precondition failed dlistimp.h 475: Cur->Next != &(List->Tail)
1770 Program asks you if you want to save changes on closing a newly opened (and unchanged) project
473 CHECK failed zone.cpp line 104: h > TmaxMech.GetHeelY()