PTP450b release date? Ship date?

When is the expected release date/ship date going to be for the PTP 450b?  When can we start turning 450b subscribers into PTP links?  My understanding was there was going to be a certain firmware/hardware revision to allow this.  I'm anxious to get my hands on these. 

PXP450b is shipping now. You cannot turn your existing PMP450b SM's into PTP units. Please see THIS post.

None of my regular suppliers seem to have them in stock.  Thanks for the info.