Every other Jest related package I've seen already is version 27, except this one. I'm not sure if that's intentional. Jest documentation states
For @types/* modules it's recommended to try to match the version of the associated module. For example, if you are using 26.4.0 of jest then using 26.4.x of @types/jest is ideal. In general, try to match the major (26) and minor (4) version as closely as possible.
I wasn't sure if the 27 work was blocked by making sure @jest/globals is ready to be used as the dependency in DefinitelyTyped (if I'm understanding the PR discussion correctly). Or if it was because there were no type changes needed for 27 release (seems kinda unlikely to me). Maybe it's just no one has gotten to it yet.
If it is just a case of no one getting to it yet, as a follow-up, is there an easy way to know what types need updated?
Jest folks confirmed 44365 is NOT blocking @types/jest 27. But they didn't know the status of @types/jest update. I don't believe any of the Jest contributors are also Jest DefinitelyTyped contributors.
A question posted in GitHub confirmed that this was just a case of the update not being done yet. But there is now a pull request to update the types.
Krisztián Balla's answer describes how to find changes between versions that might require changes to the types. Unfortunately, there's no easier way to do that, and there is nowhere you can look to know if the Jest DefinitelyTyped maintainers anticipate any changes.