iOS 7.1 has been undergoing beta testing for the last couple of weeks, and that phase in its development will continue well into March, according to previous reports. However, with every new beta release, we come one step closer to a final iOS 7.1 release. Beta 4 of the same software version is now available to testing partners and registered Apple developers. We don't have a changelog yet, unfortunately.
Apple reportedly has a total of six beta builds in plan before they move on to gold master, and a final public release which is expected to happen sometime in March.