March. In the various builds of iOS 7.1 that we've seen so far there have been UI changes like bold text and possibly a new dark theme for the keyboard, cleanup of OTA files to save you storage space, and there have been indications that the update will fix miscellaneous bugs like memory issues and random reboots.The word is that Apple is planning six builds of iOS 7.1 before finally releasing it to users sometime in
As we get newer builds of iOS 7.1, we'll obviously be seeing more and more what changes and fixes are coming. There is still at least another six weeks in development for the update, so there is definitely time for more features to come to light. We're not quite at polishing time just yet.