2.4 Release Planning

Release tracker for 2.4, the plan is to have it out by end of September.

Let me know if there's any PRs that you want to include in this release

Here are the things I want to be included in the release (most of them don't have a PR yet, but I will most likely implement these in next couple weeks):

[mypyc] Synchronize native-to-native imports #21887 should be reviewed and merged
Finish switch to the native parser by default, see Make native parser the default #21823. This one will be hopefully done in next 2-3 days.
Fix We need equivalent of parse_type_string() in native parser #21515 plus any possible fallout
Use two-phase checking in sequential checking if --local-partial-types is set (i.e. by default)
Add support for -n auto in parallel checking, see Detect number of CPUs with --num-workers auto #21477
Change logic for variadic tuple[Any, ...] (this is a long-standing thing affecting NumPy, see e.g. tuple[*Ts] subtype with extra type parameter not gradually assignable to itself #19908)
Fix remaining part of the performance regression from TypeForm, see Reduce TypeForm recognition slowdown (Take 3) #21833

Also (assuming -n auto will be done) we should announce that parallel checking will become default in a future release, and encourage people to use -n auto.

It would also be nice to include support for PEP 718 in this release, using one of these implementations

@JukkaL

@JukkaL there are couple more PRs you may want to take a look at before I merge them:

@ilevkivskyi

@ilevkivskyi I can look at the PRs tomorrow hopefully.

Btw I think it is important to get #22016 in the release. I also hope to finish #22025 soon (and it should fix some crashes).

Couple more important things for the release IMO:

@KevinRK29

@KevinRK29 @JukkaL FWIW all the changes I wanted to be included in the release are now in master. What do you think about cutting a release branch and doing the internal pin move, so that we can release early next week?

@ilevkivskyi

@ilevkivskyi yup, that sounds good with me, i can get started on it!

I’ve cut the release branch from 9d798dc

I think #22066 may be worth cherry-picking.

@KevinRK29

Also @KevinRK29 a new librt release as you asked #22067

sounds good, ill add that. thanks for the librt release!

One more thing: I think there may be an "off-by-one" problem with -n auto, I started a discussion in #21983 (comment)

Mypy 2.4 is released! https://mypy-lang.blogspot.com/2026/10/mypy-24-released.html

Regression:

[2.4 regression] type-ignore comments with mixed type-checker rule names broken #22085

I propose to close this as completed, I don't think we will need 2.4.1 (couple regressions were fixed by releasing a new ast-serialize version).

FYI, while black themselves haven't upgraded to mypy 2.4.0, we did so in Debian and now we can't mypyc-compile black anymore:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1150524

https://people.debian.org/~sanvila/build-logs/202610/black_26.10.0-1_amd64-20261010T091954.148Z

the method delimiter_split_env appears to be a mypyc version of black.linegen.delimiter_split() which has a decorator defined in the same file named dont_increase_indentation.

@JukkaL

Oh, not this again. @JukkaL @p-sawicki I think we really need to add mypyc compilation of black to mypy_primer (or a separate similar CI job). Will you have time to do this?

The regression in black should be fixed by #22187. And yeah a CI job would be very helpful, I'll work on it next.

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2.4 Release Planning #21935

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2.4 Release Planning #21935

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ilevkivskyi commented on Sep 3, 2026

KevinRK29 commented on Sep 4, 2026

ilevkivskyi commented on Sep 17, 2026

JukkaL commented on Sep 17, 2026

ilevkivskyi commented on Sep 22, 2026

ilevkivskyi commented on Sep 23, 2026

ilevkivskyi commented on Sep 25, 2026

KevinRK29 commented on Sep 25, 2026

KevinRK29 commented on Sep 28, 2026

ilevkivskyi commented on Sep 29, 2026

ilevkivskyi commented on Sep 29, 2026

KevinRK29 commented on Sep 29, 2026

ilevkivskyi commented on Sep 29, 2026

KevinRK29 commented on Oct 1, 2026

JukkaL commented on Oct 2, 2026

ilevkivskyi commented on Oct 10, 2026

mr-c commented on Oct 11, 2026

ilevkivskyi commented on Oct 11, 2026

p-sawicki commented on Oct 12, 2026

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