Ensure that all features are working now that the 1.17 API has been released.
Possible changes that might break stuff are as follows: (ticked if harmless)

• Copper changes states unless waxed
• Glowing signs exist... not sure how those will work with portals.
• Y axis can now reach values of N; can be:
  • positive
  • negative
• Slabs is now a block type.
• We now need to use java 16

Seems to be working normally