VPN is a huge priority item for everyone but like all software it takes time to get it right.
The 1.8.3 release was a quick release to fix a number of significant bugs in 1.7 and add a few enhancements. It was part of the new more frequent software release policy by Flex.
I would expect VPN support to be part of a future 1.8 Point Release - but like all software development its impossible to predict how long it will take to implement and fully test and debug it
All one can safely say is that they are working on it... and it will be delivered as soon as it is ready.