diff --git a/composer.json b/composer.json
index a83ceaf..5e88ad0 100644
--- a/composer.json
+++ b/composer.json
@@ -10,6 +10,9 @@
 			"homepage": "http://davidgrudl.com"
 		}
 	],
+	"require": {
+		"php": ">=5.2.2"
+	},
 	"autoload": {
 		"classmap": ["src/"]
 	}
diff --git a/readme.md b/readme.md
index e25669e..4e1513f 100644
--- a/readme.md
+++ b/readme.md
@@ -7,7 +7,7 @@ RSS & Atom Feeds for PHP
 
 RSS & Atom Feeds for PHP is a very small and easy-to-use library for consuming an RSS and Atom feeds.
 
-It requires PHP 5.0 or newer with CURL extension or enabled allow_url_fopen
+It requires PHP 5.2.2 or newer with CURL extension or enabled allow_url_fopen
 and is licensed under the New BSD License. You can obtain the latest version from
 our [GitHub repository](https://github.com/dg/rss-php/releases) or install it via Composer: