qcp and qtalk

I am seeing problems with qcp and qtalk on a QNX 6.2.1 setup here with
serial devices, but it works fine under QNX 6.3.0. I saw on the net
mention that there was issues with earlier versions of qcp and qtalk but I
cannot find any technical notes etc stating exactly what versions of
qcp/qtalk were affected and how.

Does anyone have information on this?