Since this method isn't private, you'll have to actually use an overridden method to add the new parameter.  Unfortunately, named/default methods aren't compiled for binary compatibility in that fashion.

IIRC you can make the override be the old arguments, and things should still work with correct defaults as before for clients.  e.g.:

```scala
def publishConfig(artifacts: Map[Artifact, File], ivyFile: Option[File], checksums: Seq[String], resolverName: String = "local", logging: UpdateLogging.Value) = publishConfig(artifacts, ivyFile, checksums, resolverName, logging, false)
def publishConfig(artifacts: Map[Artifact, File], ivyFile: Option[File], checksums: Seq[String], resolverName: String = "local", logging: UpdateLogging.Value = UpdateLogging.DownloadOnly, overwrite: Boolean = false) = ...
```

Then you just have to make sure this doesn't cause any kind of source issues, and it should be good to go.   If Scala still has the `@bridge` annotation, that should be used on the binary compatible methods if we can...