Scala 2.13.5 planning

This thread is for updates and discussions about an eventual Scala 2.13.5 release.

2.13.4 was released in November 2020. We aren’t aware of any regressions that would warrant rushing a followup. So unless something changes, the main determinant of 2.13.5 timing will be Scala 3’s release schedule. We’ll wait for 3.0.0-RC1 to be released, and then we’ll do 2.13.5 shortly afterwards, in order to update the TASTy reader.

(In the meantime, if you need a newer TASTy reader than 2.13.4 provides, you may use a 2.13.x nightly build.)

I’ve updated the 2.13.5 milestone on GitHub with a very rough target date (March 20) and release lead (me).


Last I heard 3.0.0-RC1 was supposed to release mid-Jan. You’re aiming for 2.13.5 release around March. Was 3.0.0-RC1 officially postponed?

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And he also said “M4 should be out in the first week of February” at Feedback sought: Optional Braces


Thanks, I missed that.

Another reason to do 2.13.5 in March is to ship support for JDK 16 (whose target GA date is March 16). I’m currently working JDK 16 through the Scala 2 community build:

Which has so far turned up the need to upgrade to ASM 9:

And may yet turn up other issues.

(In the meantime, people wanting to get an early start on JDK 16 testing can use our nightly builds.)


@SethTisue is there a change in 2.13.5 release estimation date due to the change in RC1 release?

We’ll discuss at team meeting today.


Yes, since 3.0.0-RC1 is now expected sooner, we will also do 2.13.5 sooner. I’ve updated the 2.13.5 milestone’s target date to February 17 (though it could certainly slip).

I haven’t been over all the 2.13.5 issues and PRs with a fine-tooth comb yet — I’ll do that this week — but we’re not aware of any real risks or blockers here.

JDK 16 support has been merged on both 2.12.x and 2.13.x.


Jamie has confirmed that he’ll update the TASTy Reader for us as soon as 3.0.0-RC1 is good to go.

I’ve finished going through all the issues and PRs and I didn’t find any other blockers.

(Some nice-to-haves might still get merged in time to be included.)

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Jamie’s TASTy reader updates are merged.

Scala 3.0.0-RC1 is on Maven Central.

But, we’re not quite ready to release 2.13.5. Getting close. A couple issues turned up when merging 2.12 changes onto the 2.13 branch — gory details on


Here’s the link to Scala 3.0.0.-RC1:

2.13.0-RC1 has now fully released and announced.

for 2.13.5, there is only one remaining issue/PR:

we still need to run the community build once this is resolved, but I’m optimistic we’ll be able to release by Tuesday.


We decided to postpone 9504 until 2.13.6.

So that means we have a release candidate: 2.13.5-bin-eb8cb18

Kicking off community build runs now. Please test it yourself if you can!

As usual, instructions for using our nightlies are at

Oh, and I should have added: we’ll release first thing Monday (US west coast time) if nothing unexpected turns up.

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Draft release notes, feedback welcome: 2.13.5 release notes by SethTisue · Pull Request #763 · scala/scala-dev · GitHub

The good news is, no further issues have come up, so we are ready to release.

The bad news is, there is GPG 1 vs GPG 2 trouble with the publishing scripts. Working on it. (Gory details at Release 2.13.5 · Issue #762 · scala/scala-dev · GitHub .)


2.13.5 JARs are now on Maven Central.

(Working on remaining release steps such as website updates.)


The compiler plugins of Scala.js 1.5.0 and Scala Native 0.4.0 are on their way to Maven Central for Scala 2.13.5.

Older versions of Scala.js and Scala Native will not work with Scala 2.13.5+.


2.13.5 is fully complete and announced!