Update README.md

Author: lrytz

README.md

@@ -5,11 +5,14 @@ Scala 2.13 Collection Compatibility Library And Migration Tool
 
 ## Compatibility Library
 
-This library for Scala 2.12 provides limited compatibility with the new collection library in 2.13. We try to keep the
-2.13 collections as backward compatible as possible but that is not always possible. For some of these cases this
-library allows you to compile sources written for a subset of the new semantics of 2.13 on 2.12.
+This library provides some of the new APIs from Scala 2.13 to Scala 2.11 and 2.12. It can be used to cross-build projects.
 
-For example, the `to` method is used with a type parameter in 2.12:
+Note that there are multiple ways to cross-build projects, see https://github.com/scala/collection-strawman/wiki/FAQ#how-do-i-cross-build-my-project-against-scala-212-and-scala-213.
+
+Also note that this library has not fully stabilized yet. We expect that new, binary incompatible releases of this library will be published (for 2.11, 2.12) until Scala 2.13 is getting close to its final state. Therefore you might want to avoid adding a dependency on that library to your 2.11 / 2.12 artifacts for the time being.
+
+
+The 2.13 collections are mostly backwards compatible, but there are some exceptions. For example, the `to` method is used with a type parameter in 2.12:
 
 ```scala
   xs.to[List]
@@ -22,10 +25,9 @@ With this compatibility library you can also use the 2.13 syntax which uses a co
   xs.to(List)
 ```
 
-This project can be cross-built on 2.13 (with new collections) and 2.12. The 2.13 version consists only of an
-empty `scala.collection.compat` package object that allows you to write `import scala.collection.compat._` in 2.13. 
-The 2.13 version has the compatibility extensions in this package. It also adds backported version of some new collection
-types to other `scala.collection` subpackages.
+The 2.13 version consists only of an empty `scala.collection.compat` package object that allows you to write `import scala.collection.compat._` in 2.13.
+The 2.11/2.12 version has the compatibility extensions in this package.
+It also adds backported version of some new collection types to other `scala.collection` subpackages.
 
 ## Migration Tool