Update caching.rst
diff --git a/user_guide_src/source/libraries/caching.rst b/user_guide_src/source/libraries/caching.rst
index 10d0e84..9c588f2 100644
--- a/user_guide_src/source/libraries/caching.rst
+++ b/user_guide_src/source/libraries/caching.rst
@@ -240,7 +240,7 @@
=============
Redis is an in-memory key-value store which can operate in LRU cache mode.
-To use it, you need Redis server and any Redis PHP extension, e.g. this one
+To use it, you need Redis server and phpredis PHP extension
`https://github.com/nicolasff/phpredis <https://github.com/nicolasff/phpredis>`_.
Config options to connect to redis server must be stored in the application/config/redis.php file.