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/Router.php b/system/core/Router.php
index d451aab..5e92a04 100644
--- a/system/core/Router.php
+++ b/system/core/Router.php
@@ -87,13 +87,13 @@
 		}
 
 		// Load the routes.php file.
-		if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/routes'.EXT))
+		if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/routes.php'))
 		{
-			include(APPPATH.'config/'.ENVIRONMENT.'/routes'.EXT);
+			include(APPPATH.'config/'.ENVIRONMENT.'/routes.php');
 		}
-		elseif (is_file(APPPATH.'config/routes'.EXT))
+		elseif (is_file(APPPATH.'config/routes.php'))
 		{
-			include(APPPATH.'config/routes'.EXT);
+			include(APPPATH.'config/routes.php');
 		}
 		
 		$this->routes = ( ! isset($route) OR ! is_array($route)) ? array() : $route;
@@ -227,7 +227,7 @@
 		}
 
 		// Does the requested controller exist in the root folder?
-		if (file_exists(APPPATH.'controllers/'.$segments[0].EXT))
+		if (file_exists(APPPATH.'controllers/'.$segments[0].'.php'))
 		{
 			return $segments;
 		}
@@ -242,7 +242,7 @@
 			if (count($segments) > 0)
 			{
 				// Does the requested controller exist in the sub-folder?
-				if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().$segments[0].EXT))
+				if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().$segments[0].'.php'))
 				{
 					show_404($this->fetch_directory().$segments[0]);
 				}
@@ -264,7 +264,7 @@
 				}
 
 				// Does the default controller exist in the sub-folder?
-				if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().$this->default_controller.EXT))
+				if ( ! file_exists(APPPATH.'controllers/'.$this->fetch_directory().$this->default_controller.'.php'))
 				{
 					$this->directory = '';
 					return array();