Is there any way to upgrade the software on a 710 to allow DivX playback? I am aware the later models come with DivX playback as standard. Does anybody know?

I don't think this is possible. However ther is a software update being run from the 30th DS thread info here.

You never know they may just be adding DivX capability, but I doubt it. Leave your 710 on BBC 4 overnight or CBeebies by day to catch the update!