Updated BC breaks notice and version guidance

Author: haphan

README.md

@@ -12,14 +12,22 @@ OpenStack services, and versions of services, are supported.
 
 * [Official documentation](http://docs.os.php-opencloud.com/)
 * [Reference documentation](http://refdocs.os.php-opencloud.com)
-* [Developer support](https://developer.rackspace.com/)
-* [Mailing list](https://groups.google.com/forum/#!forum/php-opencloud)
 * [Contributing guide](/CONTRIBUTING.md)
 * [Code of Conduct](/CODE_OF_CONDUCT.md)
 
 ## Backward incompatibility
 
-Due to new [object typehint](https://wiki.php.net/rfc/object-typehint) since PHP 7.2, class `OpenStack\ObjectStore\v1\Models\Object` had to be renamed to `OpenStack\ObjectStore\v1\Models\StorageObject`
+Due to new [object typehint](https://wiki.php.net/rfc/object-typehint) since PHP 7.2, `Object` is a reserved keyword 
+thus class `OpenStack\ObjectStore\v1\Models\Object` had to be renamed to 
+`OpenStack\ObjectStore\v1\Models\StorageObject`. See [#184](https://github.com/php-opencloud/openstack/pull/184) for 
+details.
+
+### Version Guidance
+
+| Version   | Status                      | PHP Version   | Life span               |
+| --------- | --------------------------- | ------------- | ----------------------- |
+| `^2.0`    | Maintained (Bug fixes only) | `^=7.0,<7.2`  | March 2016 - March 2018 |
+| `^3.0`    | Latest                      | `^7.0`        | March 2018 - March 2020 |
 
 ## Getting help