Scala 2.13.6 planning

This thread is for updates and discussions about an eventual Scala 2.13.6 release.

2.13.5 was released on February 22.

We’ll definitely need to do at least one release to update the TASTy reader, so perhaps that will end up being the determinant of the 2.13.6 release timing.

(We’re discussing the TASTy reader situation at fix #12357: all inline defs from tasty are treated as macros by bishabosha · Pull Request #9552 · scala/scala · GitHub


It seems the current 2.13.6 nightlies don’t support the TASTy format of 3.0.0-RC2 (3.0.0-RC2 is at 28.0.3, while 2.13.6-bin-8356365 is at 28.0.1). Is that expected? Is a bump of the format to 28.0.3 planned in 2.13.x, and in 2.13.6 in particular?

In more detail, I’m getting the following error when using 3.0.0-RC2 libraries from Scala 2.13.5 or 2.13.6-bin-8356365:

[error] (class signature has wrong version.
[error]  expected: {majorVersion: 28, minorVersion: 0 [unstable release: 1]}
[error]  found   : {majorVersion: 28, minorVersion: 0 [unstable release: 3]}

cc @bishabosha

Hi, Yes I am working on an update for Scala 2.13.6 to support the changes to TASTy and erasure rules in Scala 3.0.0-RC2, there is also planned another breaking change to TASTy coming in 3.0.0 which is to bump the TASTy version to its first ever final release.


Thanks! For the context, I ran into this error when trying to update the branch of this PR to 3.0.0-RC2 (discussed in It uses Scala 2 libraries from Scala 3 and the other way around too, so the tasty format has to match exactly. As soon as a 2.13 nightly for tasty 28.0.3 is available, it should be possible to update to 3.0.0-RC2 (and merge this PR, at last).

It seems likely that Scala 3.0 final will come out soon (at least, I haven’t heard anything about a need for an RC4…?), so we’ll do 2.13.6 soon afterwards, with Jamie’s TASTy reader update and whatever other PRs we can manage to get over the finish line.


3.0 is expected later this week and 2.13.6 is targeted for Monday, May 17 (tentatively, but we wouldn’t let it slip very far) and the release lead is Lukas. The scala/bug and scala/scala milestones have been updated; every scala/scala PR on the milestone is labeled with “prio:blocker”, “prio:hi”, or blank which means would-be-nice.


I just merged what we hope is the final 2.13.6 PR.

The release candidate is 2.13.6-bin-9468b9a.

I’ve just kicked off new community build runs. If that goes well, we could be on track for releasing early next week.


It looks good for Scala.js 1.5.1.

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I see scala3 ready to release, will there be 2.14.X in the future?

No, Scala 2.13 will be the last minor release of Scala 2. Here’s a reference that explained the plan at the time Scala 2 Roadmap Update: the Road to Scala 3 | The Scala Programming Language


Scala 2.13.6 is now on maven central, it will be announced soon.

Release notes: Release Scala 2.13.6 · scala/scala · GitHub


The sbt plugins for Scala.js 1.5.1 and Scala Native 0.4.0 are on their way to Maven Central.


Semanticdb is released for 2.13.6 and should work correctly when -Xsource:3 is set. Release Scalameta v4.4.18 · scalameta/scalameta · GitHub


We’re now officially announced.