Removing internal references to the EXT constant.  Additionally, marked the constant as deprecated.  Use ".php" instead. Also adding upgrade notes from 2.0.2 to 2.0.3.
diff --git a/system/core/Common.php b/system/core/Common.php
index 1aca809..d1e8e77 100644
--- a/system/core/Common.php
+++ b/system/core/Common.php
@@ -128,13 +128,13 @@
 		// thenin the local application/libraries folder
 		foreach (array(BASEPATH, APPPATH) as $path)
 		{
-			if (file_exists($path.$directory.'/'.$class.EXT))
+			if (file_exists($path.$directory.'/'.$class.'.php'))
 			{
 				$name = $prefix.$class;
 
 				if (class_exists($name) === FALSE)
 				{
-					require($path.$directory.'/'.$class.EXT);
+					require($path.$directory.'/'.$class.'.php');
 				}
 
 				break;
@@ -142,13 +142,13 @@
 		}
 
 		// Is the request a class extension?  If so we load it too
-		if (file_exists(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.EXT))
+		if (file_exists(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php'))
 		{
 			$name = config_item('subclass_prefix').$class;
 
 			if (class_exists($name) === FALSE)
 			{
-				require(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.EXT);
+				require(APPPATH.$directory.'/'.config_item('subclass_prefix').$class.'.php');
 			}
 		}
 
@@ -157,7 +157,7 @@
 		{
 			// Note: We use exit() rather then show_error() in order to avoid a
 			// self-referencing loop with the Excptions class
-			exit('Unable to locate the specified class: '.$class.EXT);
+			exit('Unable to locate the specified class: '.$class.'.php');
 		}
 
 		// Keep track of what we just loaded
@@ -209,9 +209,9 @@
 		}
 
 		// Is the config file in the environment folder?
-		if ( ! defined('ENVIRONMENT') OR ! file_exists($file_path = APPPATH.'config/'.ENVIRONMENT.'/config'.EXT))
+		if ( ! defined('ENVIRONMENT') OR ! file_exists($file_path = APPPATH.'config/'.ENVIRONMENT.'/config.php'))
 		{
-			$file_path = APPPATH.'config/config'.EXT;
+			$file_path = APPPATH.'config/config.php';
 		}
 
 		// Fetch the config file