Not limited to a certain version. IIRC its from firmware 1100 onwards that it displays the symbols on the Map.
However don't expect it to perform like TomTom as it won't. TomTom works off TMC and data (depending on how new it is) whereas the RNS works off Radio broadcast traffic. Hence you sometimes get told "Caution, Traffic Problems" or "You're route has been altered due to the current Traffic Situation" whilst driving on an empty motorway. Or you are stuck in traffic that according to the RNS doesn't exist.
A good example is the 50mph average speed through the roadworks on the M62. The RNS always tells me that traffic is queing for 4 miles - even at night when it's virtually empty. Whereas Co-Pilot on my iPhone will only tell me if their is heavy congestion (generally rush hour).