With Windows 10, Microsoft wants to unite your mobile and tablet with your PC.
It's made inroads before, but this is its first operating system to bring together the holy trinity. In theory, anyway.
It also brings a host of fixes and improvements that will make your phone easier to use. But how? Read on and find out.
1 Customisable backgrounds
The menu screen looks a lot like Windows Phone 8.1, with live tiles aplenty.
But there's one important difference – you can choose a background image.
Just like on iOS and Android, pick a pic and it'll take up the whole background, all the way to the corners of the screen.
The tiles are still there, but they turn translucent, so you can see your picture through them. Magic.
2 Improved Action Centre
Windows 8.1 brought a drag-down menu featuring quick settings and notifications, just like on Android and iOS. And Windows 10 improves it no end.
It adds a boatload more settings to the list – before there were only four – and lets you interact with some notifications.
In other words, you can dismiss alarms, reply to texts etc directly from the notification.
Android Lollipop brought this to Google-powered phones, so it's nice to see Microsoft catching up.
3 Better email formatting
Microsoft has also overhauled its suite of built-in apps for Windows 10.
Word is baked in to the Outlook app, so you can compose your emails in a much richer way than before.
You can even insert tables and format your text.
New gesture controls also make it easier than ever to sort your emails. Just swipe right to delete one (the opposite of Tinder) or left to flag it.
All your email action is synced to your PC, so when you open your account on your desktop, you can easily find your flagged missives.
And you won't be bothered by what you've moved to the trash.
4 One camera app to rule them all
Microsoft has finally pruned its camera software. Handsets like the Lumia 535 have two camera apps – the Windows Phone one, and Lumia Camera (aka Nokia Camera).
Thankfully Windows 10 has just one.
It's basically a rebadged Lumia Camera, with the same interface and manual controls over a host of settings.
That means Windows 10 handsets made by other manufacturers like Samsung and HTC run the same imaging software.
5 Skype integration
Much like Google Hangouts, Microsoft is bringing SMS and Skype messaging into the same thread.
So now within a conversation, you can choose to contact someone different ways without pulling out and opening a different app.
Notifications are synced across your PC.
Dismiss it from your desktop, and it'll vanish from your phone too.
The new keyboard also has a joystick that gives you greater control over the cursor for editing text.
Hopefully it should make typos a thing of the past.
Windows 10 is in preview mode now, and will launch sometime later this year.