Microsoft has already officially announced that Windows Phone 7 will see its first big update (complete with Copy & Paste) early next year, and the rumor mill has long been whispering about another update that would follow shortly thereafter. This supposed second update (which may very well be a part of that first update, depending on who you ask) would bring forth the likes of improved multi-tasking, in-app downloads, and some level of OS customizability.

And now, we’ve got yet another update to wax on about — but this one’s not coming for quite a while.

According to ZDNet’s Mary Jo Foley, the Windows Phone 7 team is crackin’ away at an update that they’ve dubbed internally as “Mango”. (Man, what’s up with all these food names? First Google tries to make me fat by naming all of their updates after desserts, now Microsoft’s labeling with fruits? I sit in front of a computer all day, guys. Stop making me hungry)

The specifics regarding what Mango might entail are a bit slim, but the original tipster mentioned at least two things on the to-do list: a Silverlight runtime (which we’re taking to mean Silverlight support in the browser), and HTML 5 support.

That’s probably not all the update will include, however, given that the same tipster implies that this update may very well be dubbed “Windows Phone 7.5″ when it finally hits handsets. With critics (including us) going a bit hard on Microsoft for launching WP7 with a laundry list of notably absent features, I’d imagine (or at least hope) that they’ll do their damnedest to make anything called “Windows Phone 7.5″ a monster.