What exactly are you getting? Lot's of fun features, including what Apple's called "emojification" and being able to pay someone via a simple text message.
First talked about by Apple at its developer conference last year, here's everything you need to know before you download it when it becomes available today
1. Snapchat by Apple?
The tech giant has taken more than a little inspiration from the hot messaging app of the moment. iMessage will now include animations, stickers and pictures, as well as instantly turning any word in to the emoji version equivalent. You can also scribble in your own handwriting instead of typing.
2. Money transfer and more
Soon, you could be making payments to your friends for dinner just my texting, as iMessage has been opened up to developers.
This means apps, such as payment apps, can be integrated into messaging, or you could book a cab if a taxi app decided to do that. On stage at WWDC, it showed off this feature with food delivery. Tasty.
3. News app
The news app is getting a makeover, and it will even include notifications. No more missing out on exactly what's going on.
4. Actually find your photos
A new way of organising your snaps will be introduced with iOS 10, with images arranged - and searchable - by things such as location or people.
5. Saved you a click
No longer will you have to go to the messaging app to respond, as Apple is adding the ability to respond straight from the notification which appears on your home screen (yes, much like WhatsApp, it's been noted).
6. Siri's even more helpful
Siri might have guided you in the right direction before, but now the helpful assistant is getting full integration with apps. That means you could request a taxi via your fave car hailing app, but you could do it all via Siri;s voice command.
7. Apple Pay online
No longer just tap ad pay in real life. With all your details already set up to do that, you'll start seeing pay with Apple Pay pop up at your favourite online destinations. that means no hassle of having to fill in card details ever again. Rejoice.