Strange Android app displaying in Mandarin
I would say the app is Baidu Browser or any other app from Baidu.

Despite not being able to see an app in the laucher, you could have some sort of malware app installed that will only display notify items but stood hidden in background. On your phone go to Settings > Application Manager and check for all the apps you have installed. If you find an app that you haven't installed, uninstalling it might end the notification issues.

If you only install apps from Google's Play Store I would suggest you disable the Unknown source option to enable/disable the installation of third party app (if you have this option enabled). You can find the option in either Settings > Security, Settings > Developement or Settings > Application Manager (depending on your Android version)

As for the ROM and updates, they can't do anything about malware apps.