"Big update" refers to a significant and major change or improvement made to something, often a software or technology, that involves substantial modifications and new features. Full definition
The next big update for the CX - 5 will be a new touch screen navigation system. (automobilemag.com)
Well that day has finally arrived, and the next big update for the game will be the last for the legacy consoles. (cinemablend.com)
Its original release wasn't all that impressive, but a steady stream of big updates over the course of the year kept making it better and better. (androidauthority.com)