Add some precisions to the readme

README.md

@@ -2,6 +2,9 @@
 
 A simple PHP client to use the [Akeneo PIM API](https://api.akeneo.com/).
 
+- The version v1.0 is compatible with the PIM 2.0.
+- The version v2.0 is compatible with the PIM 2.1.
+
 ## Requirements
 
 * PHP >= 5.6
@@ -130,5 +133,7 @@ $client->getProductApi()->upsertList([
 
 ## Support
 
+The support of this client is made in best effort by our Akeneo team.
+
 If you find a bug or want to submit an improvement, don't hesitate to raise an issue on Github.
 Also, you can ask questions and discuss about the PHP client with the community in the [Slack User Group](https://akeneopim-ug.slack.com/messages/web-api/).