diff --git a/CHANGELOG b/CHANGELOG
index a6ce11e..116bc6b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -29,3 +29,7 @@
 === 1.9.6 2014-05-12
 
 * Return empty Conekta_Object instead of empty array in Util.php
+
+=== 1.9.7 2014-05-22
+
+* Throw an exception if PHP version is not supported.
diff --git a/CHANGELOG~ b/CHANGELOG~
deleted file mode 100644
index 0adfc66..0000000
--- a/CHANGELOG~
+++ /dev/null
@@ -1,13 +0,0 @@
-=== 1.9.0 2013-01-13
-
-* Deprecate retrieve and all methods and replaced them with find and where respectively.
-* Add payment method model.
-* Objects' properties are now accessible with the T_OBJECT_OPERATOR.
-
-=== 1.9.1 2013-01-21
-
-* Add setting version functionality.
-
-=== 1.9.2 2014-04-2
-
-* Fix bugs in Resource.php.
diff --git a/lib/Conekta.php b/lib/Conekta.php
index 778bdf5..f8ba95e 100644
--- a/lib/Conekta.php
+++ b/lib/Conekta.php
@@ -8,6 +8,9 @@
 if (!function_exists('mb_detect_encoding')) {
   throw new Exception('Conekta needs the Multibyte String PHP extension.');
 }
+if (!function_exists('get_called_class')) {
+	throw new Exception('Conekta needs to be run on PHP >= 5.3.0.');
+}
 require(dirname(__FILE__) . '/Conekta/Conekta.php');
 require(dirname(__FILE__) . '/Conekta/Util.php');
 require(dirname(__FILE__) . '/Conekta/Requestor.php');
diff --git a/lib/Conekta/Conekta.php b/lib/Conekta/Conekta.php
index dcf02b1..5e1bd4f 100644
--- a/lib/Conekta/Conekta.php
+++ b/lib/Conekta/Conekta.php
@@ -4,7 +4,7 @@ abstract class Conekta
 	public static $apiKey;
 	public static $apiBase = 'https://api.conekta.io';
 	public static $apiVersion = '0.3.0';
-	const VERSION = '1.9.6';
+	const VERSION = '1.9.7';
 	
 	public static function setApiKey($apiKey)
 	{