The conflicts appear because:
- you’ve specified your Scala version to be 2.11
- you’ve explicitly specified the Scala version (2.10) for the reactivemongo and poi-scala libraries.
The fix is to use the %% operator for those two libraries as well.
"org.reactivemongo" %% "reactivemongo" % reactiveMongoVersion,
"info.folone" %% "poi-scala" % foloneVersion
That’s the purpose of the %% operator. To append the declared Scala version (2.11 in your case) to the artifact name.