NoSuchMethodError when moving to sbt 1.5.4

[Reeebuuk]

Could this be the reason why our common plugin is failing when we move from 1.3.13->1.5.4
Error like
[error] java.lang.NoSuchMethodError: 'sbt.internal.util.Init$Initialize sbt.Def$.ifS(sbt.internal.util.Init$Initialize, sbt.internal.util.Init$Initialize, sbt.internal.util.Init$Initialize)'

on this line

releaseVersionBump := { if (sys.env.getOrElse("RELEASE_PROCESS", "").matches("master_release")) Minor else Next }

Using 1.1.0.

Any hints?