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TypeScript 5.9 Iteration Plan #61648
Description
| Date | Event |
|---|---|
| 2025-02-25 | TypeScript 5.8 Release |
| 2025-05-23 | Create 5.9 Beta (5.9.0) Build for Testing |
| 2025-05-26 | TypeScript 5.9 Beta Release |
| 2025-06-13 | Create 5.9 RC (5.9.1) Build for Testing |
| 2025-06-17 | TypeScript 5.9 RC Release |
| 2025-07-18 | Create 5.9 Final (5.9.2) Build for Testing |
| 2025-07-22 | TypeScript 5.9 Final Release 🚀 |
Compiler and Language
tsc --initUpdates- 6.0 Deprecation Plans
- Investigate Cyclic Project References
node20Resolutionlib.d.tsUpdates
Activity
controversial commentedon May 5, 2025
Is the “Checked Returns for Conditional and Indexed Access Types” feature (originally #56941, now #61359) planned to re-land in 5.9?
(this feature was included in 5.8 beta, but reverted before the RC; Gabriela Araujo Britto (@gabritto) had mentioned the feature could re-land in 5.9)
DanielRosenwasser commentedon May 5, 2025
We're not planning on bringing that in for 5.9. We want to be more conservative about larger features that are more involved while so much of our attention is currently on the port.
controversial commentedon May 5, 2025
understood, thanks for clarifying Daniel Rosenwasser (@DanielRosenwasser)
should we expect that that feature (or others of similar scope) won’t land in Typescript until 7.x?
i.e. should we expect it will never land in Strada—in order to avoid the additional development burden of trying to port a “moving target”—but instead the team will hold off until Corsa is ready to be the target of new features like this one?
(to be clear, that approach would not be at all unreasonable to me, just curious what to expect!)
ltdu commentedon May 6, 2025
There is a typo in planning table - all dates are for previous year :)
DanielRosenwasser commentedon May 6, 2025
Tautvydas Duda (@ltdu) fixed, thank you!
Luke Deen Taylor (@controversial) I can't say that for sure - we generally won't plan on new features, but it depends on priority, finding improvements that need to be backported during the port, etc. We just don't want to split our focus too much.
nicolo-ribaudo commentedon May 15, 2025
Hi! Is there any plan to include #59391, which is already at Stage 3?
(I understand if no given your other comments, but still asking because maybe JS features have higher priority)
petamoriken commentedon May 15, 2025
I hope #61236 will be included too.
nnnnoel commentedon Jun 20, 2025
Any updates about release date? It seems RC version not released.
Renegade334 commentedon Jul 1, 2025
Presumably we're too late for an
es2025target?DanielRosenwasser commentedon Jul 2, 2025
Sorry for the delay all. It has been a busy while and so we're off schedule. Time to get things rolling again though!
TypeScript Bot (@typescript-bot) create release-5.9
typescript-bot commentedon Jul 2, 2025
Starting jobs; this comment will be updated as builds start and complete.
create release-5.9DanielRosenwasser commentedon Jul 2, 2025
TypeScript Bot (@typescript-bot) create release-5.9
typescript-bot commentedon Jul 2, 2025
Starting jobs; this comment will be updated as builds start and complete.
create release-5.917 remaining items
DanielRosenwasser commentedon Jul 31, 2025
TS 5.9 is now available! Release blog post pending.
jogibear9988 commentedon Aug 17, 2025
Is there also a plan for the next one?
DanielRosenwasser commentedon Sep 25, 2025
TypeScript Bot (@typescript-bot) bump release-5.9
typescript-bot commentedon Sep 25, 2025
Starting jobs; this comment will be updated as builds start and complete.
bump release-5.9typescript-bot commentedon Sep 25, 2025
Hey, Daniel Rosenwasser (@DanielRosenwasser)! I was unable set the version.
Check the logs at: https://github.com/microsoft/TypeScript/actions/runs/18022473945
jakebailey commentedon Sep 25, 2025
TypeScript Bot (@typescript-bot) bump release-5.9
typescript-bot commentedon Sep 25, 2025
Starting jobs; this comment will be updated as builds start and complete.
bump release-5.9typescript-bot commentedon Sep 25, 2025
Hey, Jake Bailey (@jakebailey)! I've set the version of release-5.9 to 5.9.3 for you.
controversial commentedon Nov 21, 2025
Daniel Rosenwasser (@DanielRosenwasser) I think this issue can be closed since ts5.9 has been released for a few months
will there be a TS 5.10 or the team is focused on typescript 6 next?
ghiscoding commentedon Nov 25, 2025
I think part of your question can be answered by reading the Announcing TypeScript 5.9 blog post
and looking at the latest versions on NPM too, it's obvious that 6.0 will be the next release. Also FYI, there's never been any
x.10version since that is the transitioning number to their new major release (TypeScript doesn't follow semver for their release, they go from 0-9 as minor and then bump to a new major after that)What I'm curious to know is when exactly is 6.0 supposed to come out? Because looking at the previous releases, November is typically a release month for TypeScript but December is almost here so... and also, will it include any major breaking changes? There's a couple that we can see in the 6.0 milestone and mostly this one #54500
It would be nice to get more news from core team though and/or an official planning issue like this one.
RyanCavanaugh commentedon Nov 25, 2025
Stay tuned for a blog post (probably in the next week or so), but 6.0 will be later than the usual cadence. The issues you linked outline all our planned breaking changes for that release.
jogibear9988 commentedon Nov 25, 2025
you can also look here: #62785
DanielRosenwasser commentedon Feb 3, 2026
The 6.0 iteration plan was just posted over at #63085.