This is the release note of v3.1.1.

Enhancements

• [Backport] Import cmaes package lazily (#4573)

Bug Fixes

• [Backport] Fix botorch dependency (#4569)
• [Backport] Fix param_mask for multivariate TPE with constant_liar (#4570)
• [Backport] Mitigate a blocking issue while running migrations with SQLAlchemy 2.0 (#4571)
• [Backport] Fix bug of CMA-ES with margin on RDBStorage or JournalStorage (#4572)
• [Backport] Fix RDBStorage.get_best_trial when there are infs (#4574)
• [Backport] Fix CMA-ES Sampler (#4581)

Code Fixes

• [Backport] Add types-tqdm for lint (#4566)

Other

• Update version number to v3.1.1 (#4567)

Thanks to All the Contributors!

This release was made possible by the authors and the people who participated in the reviews and discussions.

@HideakiImamura, @contramundum53, @not522