Code change LGTM but can I just double check, is the intent that we will continue to backport each patch release for bbolt release-1.3 branch into etcd 3.4 and 3.5 stable releases, or is it case by case depending on what each patch release of bbolt actually contains?

I guess patch version update is backportable while etcd 3.6 will depend on bbolt 1.4 like https://github.com/etcd-io/etcd/blob/main/Documentation/contributor-guide/roadmap.md documented.

• v1.3.8 has a couple of bug fixes, such as panicking on arm32 etc. It's highly recommended to bump the version. Especially we will support 3.4 for a long time ( > 0.5 years). (Note actually many people are still not willing/ready to upgrade to 3.5);
• If you compare the differences between 1.3.7 and 1.3.8, it should be safe.
• I wish 1.3.8 is the last patch for bbolt release-1.3.