Yes, we know it'll be Spring down here. No, we're not going to change the name. It's the Autumn Update, you'll have to live with it, southern hemisphere seasonal nitpickers.
Anyway, what you'll actually find in Psyonix's next update is the conclusion to season 5 - which of course means that Competitive Season 6 is also kicking off.
On top of that there's Farmstead, a new seasonal arena, which is available for a limited time, 90 free new customisation items, customisable player banners, transparent goals posts (there's a joke about moving the goal posts here), and even LAN support for the PC version of the game.