KUAL still works on the KV.
So Amazon "deprecated" it and doesn't support further Kindle Store sales of Active Content. (I don't think they were overly impressed with the success of Active Content in the store.)
But they haven't actually removed support from the firmware.
All you need to do is use the
MobileRead shared developer keystore to sign your Kindlets and run them on jailbroken devices.
Wiki:
Kindlet_Developer_HowTo#Developing_Java_Kindlets