Problems updating from Evergreen (11.4)

I finally got around to updating the wife’s laptop today. It’s running 11.4
(Evergreen) so I figured to try the tested method of 11.4 → 12.3 → 13.1.
That’s been pretty reliable but this lappy threw a wrench into the works:
the partitions are formatted ext3 and that gives both 12.3 and 13.1 fits -
both see the root partition but refuse to recognize the format on the /home
partition. 11.4 has no problem with the home partition but I like some
input on how to proceed with the update - I don’t relish the fallout if I
lose her home data…

Both root and home partitions have current backups (rsync via lucky backup)
so I have some breathing room. I would prefer to get both partitions up to
ext4 while I’m at it and I want to end up with 13.1 on the machine, The
biggest reason for the 12.3 step is that updating some other machines has
shown that the intermediate step to 12.3 does a much better job of winding
up with a good migration of the KDE PIM data - I’ve had issues going
straight to 13.1 on some of the boxes.

  1. Can anyone give some insight on why 12/13 refuse to recognize the ext3
    format on that /home partition when 11.4 has no problem (11.4 fsck is
    perfectly happy with it)? Would running fsck from a 12.3 or 13.1 live dvd
    likely do any good?

  2. Is there any way (unlikely, I admit) to do an in-place translation from
    ext3 to ext4?

  3. Any gotchas if I reformat both partitions to ext4 then restore from
    backup? Can I expect the restored backup to boot 11.4?

Will Honea