As announced on the official Nintendo website, Splatoon 2 will be updated to version 3.0.0 today from around 18:00 PT, which equates to around 02:00 the next morning in the BST timezone.
In terms of what's coming, the website has the full list of extensive patch notes, but the highlights include more gear coming to the shop, a new rank type called X Rank, two new songs that'll play during multiplayer matches, and the usual amount of bug fixes and tweaks.
Are you still playing Splatoon 2 regularly?