Apple has released the beta of iOS 7.1 to developers.
iOS 7.1 beta, build 11D5099e, has the usual bug fixes and performance enhancements that come from such a build. But, as 9to5Mac points out, noticeable improvements include the ability to upload burst-mode photos to Photo Stream and a dark keyboard option that can be accessed through the Accessibilities settings. Other tweaks include an auto-HDR mode for the Camera and tweaked text in Notification Center.
The betas are available through the iOS Developer Center.