Made Environment Support optional. Comment out or delete the constant to stop environment checks.
diff --git a/system/libraries/User_agent.php b/system/libraries/User_agent.php
index 11af214..04cda73 100644
--- a/system/libraries/User_agent.php
+++ b/system/libraries/User_agent.php
@@ -84,7 +84,7 @@
 	 */
 	private function _load_agent_file()
 	{
-		if (is_file(APPPATH.'config/'.ENVIRONMENT.'/user_agents'.EXT))
+		if (defined('ENVIRONMENT') AND is_file(APPPATH.'config/'.ENVIRONMENT.'/user_agents'.EXT))
 		{
 			include(APPPATH.'config/'.ENVIRONMENT.'/user_agents'.EXT);
 		}