It should be fine, except that the names of the start/end.gcode files have moved from Export to the new Bookend module - check that Bookend has the right names for your profile - and that the Max Z Feed Rate value has moved from Limit to Speed so also check that one.
You might want to give it a day or so before upgrading or use the nightly build instead as there have been a couple bugs found in 42. Enrique has been
very quick on fixing these so I'm hopeful that 43 (or 42a or something) will be out soon.
