The plugin manager in 6.2 is primitive. You can only load one VST instrument per staff (no multi-timbral Kontakt instances without heavy routing). Forget about real-time MIDI recording with quantized notation—latency compensation is poor.
The release addressed numerous minor bugs and stability issues present in earlier 6.x builds, making it the most stable version of the Sibelius 6 series. The "Last of Its Kind" Legacy sibelius 6.2