Does sbt build against scala 2.11?

Question

I want to write a plugin using scala 2.11

sbtPlugin := true

scalaVersion := "2.11.0"

The current sbt release (0.13.9) is built on scala 2.10.5 https://github.com/sbt/sbt/blob/0.13.9/build.sbt#L27

EDIT: Does build against 2.11 in the community build.

https://scala-ci.typesafe.com/job/scala-2.11.x-integrate-community-build/lastSuccessfulBuild/consoleFull
[sbt] --== Extracting dependencies for sbt ==--
[sbt] Fetching https://github.com/sbt/sbt.git
[sbt] into /home/jenkins/workspace/scala-2.11.x-integrate-community-build/target-0.9.1/clones/d12473907f59fe78661e5f2a758557fe14df3ac6
[sbt] Took: 00h 00m 02.3s
[sbt] Fetching /home/jenkins/workspace/scala-2.11.x-integrate-community-build/target-0.9.1/clones/d12473907f59fe78661e5f2a758557fe14df3ac6
[sbt] into /home/jenkins/workspace/scala-2.11.x-integrate-community-build/target-0.9.1/extraction/18f58ea36720e88c2e79edce7efe5b626fc09a5e/projects/c2c0436b24853ab78d6f35ecf52a77248da4e537
[sbt] Took: 00h 00m 01.3s
[sbt] The following subprojects will be built in project sbt: launcher-interface, test-agent, control, io, datatype-generator, process, scripted-framework, interface, launcher, precompiled-2_8_2, relation, classpath, api, precompiled-2_9_2, logging, compile, run, classfile, scripted-sbt, testing, incremental-compiler, persist, compiler-integration, precompiled-2_9_3, compiler-interface, collections, completion, logic, apply-macro, tasks, task-system, cache, tracking, cross, ivy, compiler-ivy-integration, actions, command, main-settings, main, sbt, scripted-plugin
[sbt] --== End Extracting dependencies for sbt ==--

Answer 1

sbt now uses Scala 2.12

The current version of sbt is 1.2.8 (released 30th December 2018) and it supports Scala 2.12 since 1.0.0 (released 10th August 2017)

sbt 1.0 uses Scala 2.12 for build definitions and plugins. This also requires JDK 8.

https://www.scala-sbt.org/1.x/docs/sbt-1.0-Release-Notes.html#sbt+1.0.0

We simply skipped Scala 2.11 and went directly to 2.12.

Answer 2

We can't break binary compatibility for all the sbt 0.13 plugins until we release the next version sbt 0.14 or potentially sbt 1.0, so no Scala 2.11.x sbt until then.

Update:

One way to work around this is to use Fork API. sbt 0.13 is capable of building Scala 2.11 source using Scala 2.11 compilers. You can mimic the way its done, and run Scala 2.10 or 2.11 code from sbt.