Hi,
A customer case identified a bug in Lagom’s sbt plugin: not being able to cross-build Lagom applications with difference Scala versions (such as Scala 2.12 and 2.13).
The fix for this was found and it is the reason we’ve released Lagom 1.4.15.
See for more info https://github.com/lagom/lagom/releases/tag/1.4.15.
Enjoy,
the Play Team