While you are questing, you can now find a new button in the pause menu - Save & Quit. Pressing this button will create a checkpoint savefile that you can resume from at a later time.
Previously, to stop playing you would need to return to Base Camp and end your current quest. But now, you can just suspend the game and come back another time. So when real life calls, you'll no longer be caught out!
You can use this feature at almost any time - but not during combat and not during a dungeon. Resuming will restore your location in the world and all your progress too (like your mount, ammo and collected pins). But the overworld's patches will also be reshuffled.
There's one more benefit - if you are within the minority of players that suffers from occasional crashing, then this feature also allows you to resume your crashed quest. An automatic save will be made before the game crashes, allowing you to resume from the previous room you cleared.
And finally, it's important to note that each checkpoint file can only be loaded one time! This is needed to stop players making a checkpoint right before a tough encounter and then reloading that savefile over and over again! Patch Quest is meant to be a challenging (yet fair) game, so it's important to prevent infinite reloading of the same checkpoint. But you can save, quit and resume your quest as many times as you need to.