Since 2000 (when I started flying it), there has been no change in the SFO-FRA schedule. There is a new second service being added this spring which has not been in the schedule before, it may fail and be removed, but other than that, do not expect the int'l portions of your travel to experience schedule changes.

PS - Personally, I hope the new 2nd daily service isn't a flop, it gives me more opportunities for alternate routings.