Two very interesting bits have emerged from the leaked Windows Phone 8.1 SDK, which now seems always has something to reveal.
Windows Phone 8.5 will follow Windows Phone 8.1 as the next OS update. As can be seen in the second image above, the warning pops up saying “secondary tiles me not available in Windows Phone 8.5“, which may hint about some UI changes on-board in Windows Phone 8.5.
The limitation of 30 min for apps background update is removed in Windows Phone 8.1 and now 1 minute background update may be possible.