Wunderkit will remain stable for some time yet. Once Wunderlist 2 is ready we will be offering an export tool, so that your friends and family will be able to transfer their data directly from Wunderkit to Wunderlist 2.
Thanks for the reply Christian. I'll be sure to let them know if that fact. I respect the nature of the decision, and i know it was certainly not an easy one. You've handled it very well, and the communication around that fact very well.