This version is 10 builds ahead of the last known leak and so far has not been officially released by Microsoft. It is currently on their servers however and as the release date for MSN 8 and MSN messenger 5 are only a few days away this will most likely be the release build.
This version connects faster than the 4.7 builds currently supported by Microsoft as well as being able to send files out beyond a router without doing manual configuration of ports.
Ad-Remover (removes MSN banner ad)
thanks to iexbeta & tehboard