Microsoft is always looking to enhance its Windows Phone platform and on occasion, Microsoft's Joe Belfiore takes to Twitter to provide an updates on the current status of many highly requested items. To that extent, Belfiore gave a small update about Skype, Facebook and the lockscreen app that was first showed of at BUILD 2014.
Skype and Facebook updates will be arriving in the near future as they are currently in development; the lockscreen app is currently in testing and should hit the 'preview' stage soon. Typically, Microsoft releases a preview of the app (beta) and then pushes out the final build a few weeks later. According to Belfiroe's tweets, that is the same plan for the lockscreen app as he said "New lock screen app-- probably a couple weeks as beta for 1GB devices. A bunch of us are running it now, working on polish. dev-preview next".
It's important to note in his statement that it would appear that Windows Phone devices with less than 1GB of RAM will not be able to run the lockscreen app.
As for Windows Phone 8.1, the code is done and Microsoft is currently testing the update process which is needed to bring all existing Windows Phone 8 devices up to 8.1. Seeing that there are quite a few different Windows Phones out in the wild running Windows phone 8, there are a plethora of scenarios that must be fully vetted before the code can be pushed down to handsets.
Based on previous leaks for a market in Europe, it looks like the target to push out Windows Phone 8.1 will be around the middle of Summer. You can check out the roadmap here but know that it was an internal document and the timelines are subject to change. More so, this is for one market in Europe, so the US may have a different schedule too.
The good news here is that Microsoft is still continuing with its theme of transparency. While not the most detailed update about the progress of the apps or the 8.1 release, at least the company is providing some nuggets of information.
Source: Joe Belfiore