Microsoft Confirm Yearly Update

Microsoft release a new OS last year call WIndows Phone 7, many top carrier such as Samsung, HTC are using   it. In order to keep up with other competitor especially Android and IOS the WP7 OS need to have an update and MIcrosoft has confirm an update yearly, hopefully or else they lose in the dark. With the first and upcoming update coming the MANGO update folliwing after the NoDo update which is still yet to be seen on the some WP7 smartphone, how will Microsoft live up to its promise?