[DOCS] Tweak the version matrix

README.md

@@ -18,15 +18,18 @@ Features
 
 Version Matrix
 --------------
-Since there are breaking changes in Elasticsearch 1.0, you need to match your version of Elasticsearch to the appropriate version of this library.
-If you are using a version older than 1.0, you must install the `0.4` Elasticsearch-PHP branch.  Otherwise, use the `1.0` branch.
-
-The master branch will always track Elasticsearch master, but it is not recommended to use `dev-master` in your production code.
 
 | Elasticsearch Version | Elasticsearch-PHP Branch |
 | --------------------- | ------------------------ |
-| >= 1.0                | 1.0                      |
-| <= 0.90.*             | 0.4                      |
+| >= 2.0 (unreleased)   | Master                   |
+| >= 1.0, < 2.0         | 1.0                      |
+| <= 0.90.x             | 0.4                      |
+
+Since there are breaking changes in Elasticsearch 1.0 (and 2.0 when it is released), you need to match your version of Elasticsearch to the appropriate version of this library.
+
+ - If you are using Elasticsearch 1.0+, you must install the `1.0` Elasticsearch-PHP branch.
+ - If you are using a version older than 1.0, you must install the `0.4` Elasticsearch-PHP branch. Since ES 0.90.x and below is now EOL, the corresponding `0.4` branch will not receive any more development or bugfixes.  Please upgrade.
+ - You should never use Elasticsearch-PHP Master branch, as it tracks Elasticearch master and may contain incomplete features or breaks in backwards compat.  Only use ES-PHP master if you are developing against ES master for some reason.
 
 Documentation
 --------------