• new feature: metadata uuid
  • lightweight change of UUID without rewriting all metadata (incompatible change)
  • done by btrfstune -m/-M, needs kernel support, 5.0+
• image: fix block groups when restoring from multi-device image
• image: only enlarge result image if it's a regular file
• check: more device extent checks and fixes
• can repair dir item with mismatched hash
• mkfs: uuid tree created with proper contents
• fix mount point detection due to partial prefix match
• libbtrfsutil: fix tests if kernel lacks support for new subvolume ioctls

Created a partition, copied data on it, shrinked it and checked it. In console and GParted, all fine.