diff --git a/.travis.yml b/.travis.yml
index 61ab88d..015fc22 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,6 +10,7 @@ php:
     - 7.1
     - 7.2
     - 7.3
+    - 7.4
 
 env:
     global:
diff --git a/src/CachePlugin.php b/src/CachePlugin.php
index 805d361..f637689 100644
--- a/src/CachePlugin.php
+++ b/src/CachePlugin.php
@@ -17,7 +17,9 @@
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
 /**
- * Allow for caching a response.
+ * Allow for caching a response with a PSR-6 compatible caching engine.
+ *
+ * It can follow the RFC-7234 caching specification or use a fixed cache lifetime.
  *
  * @author Tobias Nyholm <tobias.nyholm@gmail.com>
  */