It's not too late to register for the //learn/ Windows Phone event. If you haven’t heard about this event it’s an online webcast series hosted by Microsoft and delivered by MVPs in a number of different languages (hopefully one that suits you!). Over 6 hours you’ll learn about a lot of the key new features of Windows Phone 8.1 and how you can build awesome Universal applications for the Windows platform.
Here's a quick view of the schedule:
There are more details here - http://nicksnettravels.builttoroam.com/post/2014/04/23/LEARN-Sessions-for-Tomorrow.aspx