As I said, I am not sure about the fan stream, but for the core stream, most modern aircraft engines have three 'critical cross sections' (cross section with an fluid Mach number of EXACTLY 1).
HPT inlet guide vanes
LPT inlet guide vanes
The reason for this is simple. A turbine running between two critical cross sections is running at a totally contant pressure ratio (at least when running above a certain thrust setting like during cruise, climb and takeoff), and can therefore be highly optimized for that pressure ratio. A compressor has a variety of different inlet pressures, velocities and temperatures which it has to work with, thats one of the reason why compressors have effiencies of 'only' about 85% to 90%, whereas latest generation turbines (running on next-generation engines) are around 97% or 98%.
For the fan stream, I think that with a high cruise speed, the exhaust velocity can be Mach 1 also, remember that the inlet Mach number is already around M 0.6 and cruise speed of a 747SP can be around 0.92. one should also consider, that if the Mach numbers
for both core and bypass a 1.00, the velocity
of the core can be easily 40 or 50% higher, usually around 500 meters / second
Exhaust mach number for a civil aerospace engine can never exceed Mach 1, since the nozzles cannot accelerate the steam further than Mach 1.
P.S. Please excuse my crappy engieering english, hope it was understandible