Hi Gene,
I think there's been some discussion about library migration and favorite migration. I try to summarize it.
Library migration is supported with migration libraries. You should not load AC11, AC12 and AC13 libraries together. You should load AC13 lib and the two incremental migration libraries instead. This gives relevant efficiency gain but it won't make you totally comfortable.
Favorite migration isn't solved between incompatible libraries:( So if you don't want to redo you favorites, you have to keep the related library parts. Migration libraries give some aid for that...
I hope migration libraries can ease your work at least a bit.
Regards,
Zsolt
Zsolt Táskai
ArchiCAD Development - GDL Team
AC13, AC14 and upwards...