You can find it on crates.io or on GitHub. Notice that as it's a release candidate, you have to specify the version for it to be selected, it's not automatic.

Please test it on all the strange use cases you have, update the plugins you maintain, and get ready for an exceptional release! The migration guide is still being worked on, but the draft can already prove useful.

For the next two weeks, we'll cherrypick back to the release branch merged PRs from the 0.14 milestone, so that they will be in the 0.14 release. While we will avoid breaking changes, it's still a possiblity one will be merged if there's a big enough issue.