This issue summarizes changes of the future Minecraft 1.17 update

• Lava can be placed in Cauldron
  • Collecting water from cauldrons with buckets in Creative mode were inconsistent.
• Catching a fish in Creative mode doesn't give player a new bucket https://bugs.mojang.com/browse/MC-189535
• Axolotl Bucket ✅
  • Axolotls can be fed with buckets of tropical fish: axolotl_tempt_items tag
  • https://bugs.mojang.com/browse/MC-208649
  • https://bugs.mojang.com/browse/MC-208654
• Powder Snow Bucket (Snow Cauldron)
• milk from goats ✅
• MC-136776 – Some NBT tags are not kept when fish or axolotl mobs are caught in water buckets https://bugs.mojang.com/browse/MC-136776

Not included changes:

• new Clay/Ceramic Pot mechanism
  • up to 8 ceramic shards can be added
  • can be fired by fire under the pot
• Cauldron can be filled/emptied with dispenser (water, lava, snow)

Porting TODOs:

• Remove old fish buckets ✅
• Fill/Empty cauldron with ceramic bucket

Forge changes:

• 1.16.5-36.0.40 FluidUtil changes
• 1.17 FluidUtil / Fluid Capability changes

This issue is fixed by using the library mod BucketLib