23 silverlight apps on windows phone 8.1 22 universal apps for windows 21 app packaging, monetization and publication 20 tooling and diagnostics 19 programming sq lite on windows phone 8.1 17 camera, media, and audio in windows phone 8.1 16 interacting with user data contacts and appointments 15 sensors and proximity nfc and bluetooth 14 tiles, notifications, and action center 13 networking, mobile services, and authentication 12 maps, geolocation, and geofencing 11 background tasks and multitasking 10 sharing files and data in windows phone 8 09 data storage, backup and roaming 
