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/libraries/Calendar.php b/system/libraries/Calendar.php
index 72d228e..df0fd6e 100644
--- a/system/libraries/Calendar.php
+++ b/system/libraries/Calendar.php
@@ -47,7 +47,7 @@
 	{
 		$this->CI =& get_instance();
 
-		if ( ! in_array('calendar_lang'.EXT, $this->CI->lang->is_loaded, TRUE))
+		if ( ! in_array('calendar_lang.php', $this->CI->lang->is_loaded, TRUE))
 		{
 			$this->CI->lang->load('calendar');
 		}
diff --git a/system/libraries/Driver.php b/system/libraries/Driver.php
index b942f53..d1925c0 100644
--- a/system/libraries/Driver.php
+++ b/system/libraries/Driver.php
@@ -59,7 +59,7 @@
 					// loves me some nesting!
 					foreach (array(ucfirst($driver_name), $driver_name) as $class)
 					{
-						$filepath = $path.'libraries/'.$lib_name.'/drivers/'.$class.EXT;
+						$filepath = $path.'libraries/'.$lib_name.'/drivers/'.$class.'.php';
 
 						if (file_exists($filepath))
 						{
diff --git a/system/libraries/Encrypt.php b/system/libraries/Encrypt.php
index e5f6587..b30a8cf 100644
--- a/system/libraries/Encrypt.php
+++ b/system/libraries/Encrypt.php
@@ -524,7 +524,7 @@
 		{
 			if ( ! function_exists('mhash'))
 			{
-				require_once(BASEPATH.'libraries/Sha1'.EXT);
+				require_once(BASEPATH.'libraries/Sha1.php');
 				$SH = new CI_SHA;
 				return $SH->generate($str);
 			}
diff --git a/system/libraries/Log.php b/system/libraries/Log.php
index fb2c5a4..9f1db76 100644
--- a/system/libraries/Log.php
+++ b/system/libraries/Log.php
@@ -83,7 +83,7 @@
 			return FALSE;
 		}
 
-		$filepath = $this->_log_path.'log-'.date('Y-m-d').EXT;
+		$filepath = $this->_log_path.'log-'.date('Y-m-d').'.php';
 		$message  = '';
 
 		if ( ! file_exists($filepath))
diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index e80049f..3177424 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -945,13 +945,13 @@
 
 		if (count($this->mimes) == 0)
 		{
-			if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/mimes'.EXT))
+			if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/mimes.php'))
 			{
-				include(APPPATH.'config/'.ENVIRONMENT.'/mimes'.EXT);
+				include(APPPATH.'config/'.ENVIRONMENT.'/mimes.php');
 			}
-			elseif (is_file(APPPATH.'config/mimes'.EXT))
+			elseif (is_file(APPPATH.'config/mimes.php'))
 			{
-				include(APPPATH.'config//mimes'.EXT);
+				include(APPPATH.'config//mimes.php');
 			}
 			else
 			{
diff --git a/system/libraries/User_agent.php b/system/libraries/User_agent.php
index 04cda73..016102a 100644
--- a/system/libraries/User_agent.php
+++ b/system/libraries/User_agent.php
@@ -84,13 +84,13 @@
 	 */
 	private function _load_agent_file()
 	{
-		if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/user_agents'.EXT))
+		if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/user_agents.php'))
 		{
-			include(APPPATH.'config/'.ENVIRONMENT.'/user_agents'.EXT);
+			include(APPPATH.'config/'.ENVIRONMENT.'/user_agents.php');
 		}
-		elseif (is_file(APPPATH.'config/user_agents'.EXT))
+		elseif (is_file(APPPATH.'config/user_agents.php'))
 		{
-			include(APPPATH.'config/user_agents'.EXT);
+			include(APPPATH.'config/user_agents.php');
 		}
 		else
 		{