Nokia is great at releasing firmware updates to a bit older hardware, the most recent being the Nokia E72 to get updated. In my opinion, the Nokia E72 was once one of the best QWERTY-smartphone out there without touch. It was released all the way back in 2009, so a new firmware almost three years after the hardware release is noteworthy.
This new update will pump the version number from 81.003 to 91.003. A change log is so far unknown.
Keep in mind that software updates are usually pushed out in phases. Keep on checking for possible updates until you get this ;)