TOML 1.1 is now enabled by default. The TOML changelog has an overview of changes: https://github.com/toml-lang/toml/blob/main/CHANGELOG.md

Also two small fixes:

• Encode large floats as exponent syntax so that round-tripping things like 5e+22 is correct.

• Using duplicate array keys would not give an error:

  arr = [1]
  arr = [2]

  This will now correctly give a "Key 'arr' has already been defined" error.