I heard some one got it.
SinKing Mar 20 2014, 7:10pm says:
The best thing is - I bought a UDK 99$ license last year and for my support I now get free access to UE4, until December 31st, 2015. Massive thanks to EPIC for that!
I bought a UDK 99$ license last year too.I wonder how I can get the same favour?
My license is a link
https://www.unrealengine.com/udk/licensing/show/?license=2905101664
however I can’t open it anymore?
I doubt it’s true, he must of been a UE4 BETA tester because that’s the deal we have.
I have UDK license and I was a UE4 BETA tester, neither are related.
Netbaixc, I FWDed this thread to our support guys to take care of you. You are right that as a token of our appreciation we provided people that purchased a $99 UDK license with free UE4 subscription through EOY 2015. I’m sorry the email on how to claim it didn’t make it to you. We have you covered though 
Great!can’t wait to join the ue4!
Thank you very much!
So I will wait for the email?
My email is still the one I registered when applying the udk license.It is
Waiting…
I FWDed your email to folks that will take care of you and you should receive an email from them. Drop me an email at daniel.vogel@epicgames.com in case you don’t hear from anyone or the issue isn’t resolved by the end of the week.
Wait… why would they get 2 years of UE4 for purchasing UDK? That’s $420, not $99!
Because Epic are awesome?
(To be clear, I didn’t purchase UDK - i still think it’s awesome)
Is it possible to build a time machine for under $320 and purchase UDK?
That could probably be done with Blueprints.
Thank you Daniel!I have received email,and I have gotten the ue4,including the source code.So Epic are really awesome!