diff --git a/config/config.sample.php b/config/config.sample.php
index 4646de3308..d106d03f60 100644
--- a/config/config.sample.php
+++ b/config/config.sample.php
@@ -1062,7 +1062,8 @@ $CONFIG = array(
  * Only for use with Redis Clustering, for Sentinel-based setups use the single
  * server configuration above, and perform HA on the hostname.
  *
- * Redis Cluster support requires the php module phpredis in version 3.0.0 or higher.
+ * Redis Cluster support requires the php module phpredis in version 3.0.0 or
+ * higher for PHP 7+ or phpredis in version 2.2.8 for PHP 5.6.
  *
  * Available failover modes:
  *  - \RedisCluster::FAILOVER_NONE - only send commands to master nodes (default)