Scala SBT - How to force/require a specific SBT version

To specify the version of SBT you want to use on your SBT project, specify the sbt.version configuration parameter in the project/build.properties file in your SBT project:

sbt.version = 1.2.6

For example, if your project directory is named /Users/Al/Foo, the file would be here:

/Users/Al/Foo/project/build.properties

You can currently find more information about this setting on this scala-sbt.org page.