latest Atmega644?

hi
I have the latest version Atmega644 20Mhz "20140809",
I saw for Atmega644 there is version "20141022" is it possible to install it? and where to download?
I have the latest version Atmega644 20Mhz "20140809",
I saw for Atmega644 there is version "20141022" is it possible to install it? and where to download?