Update sent out for Microsoft Surface RT users
showed limited access for Wi-Fi connectivity. The update also improves performance with Windows itself, and the volume and power buttons. To see if you received the update, you can click on the upper right portion of the screen or swipe in from the right edge. Click on Settings, and tap on Change PC settings. Then, tap on Windows Update and Check for Updates.
The January update repaired issues with the audio when the tablet was in Connected Standby, and added additional capabilities for firmware updates when the battery is low. The December update was supposed to reduce the scenarios that woukd result in the limited Wi-Fi notice, and also added non-standard-ASCII special characters such as: ñ, ö, ü, á, é to Access Point names.
source: Microsoft (1), (2) via Engadget