[ci skip] Prepare 3.1.5 release
diff --git a/composer.json b/composer.json
index 0a898d2..c40d549 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
 		"source": "https://github.com/bcit-ci/CodeIgniter"
 	},
 	"require": {
-		"php": ">=5.2.4"
+		"php": ">=5.3.7"
 	},
 	"suggest": {
 		"paragonie/random_compat": "Provides better randomness in PHP 5.x"