Paul Thurrott, who is eternally on the inside track for Windows Phone info, has released the update schedule for WP7 over 2011. There will be a small called NoDo update announced in January, landing in February:
This update will include the famed copy and paste functional addition, support for the Qualcomm 7×30 smart phone chipset, a CDMA location stack, and a number of software fixes.
Later in the year will come the “Mango” update (rumored for August/September), either to be Windows Phone 7.2 or Windows Phone 7.5, which will be much larger.
…this will add Internet Explorer 9 with with the Trident 5 rendering engine, HTML 5 and Silverlight, and gesture support… Internally, this code branch is referred to as the “entertainment” branch, which suggests other, non-IE functionality as well.
Mango won’t come directly after after NoDo, there may be other small updates in-between.
There are more details at the original article, so go and have a read, and report back with your thoughts.