This question has come up a lot in the last few days, so it’s worth addressing again.
Up until you reach level 26, your XP bar is blue. It fills up normally and when it’s full, you get a pop-up telling you that you’ve reached the next level, like this one:
When you get to level 26 (the highest level at the date of this post), the XP bar is still blue, but a little gift box appears at the end of it which indicates that you won’t be leveling up once the XP bar is full this time and you’ll be hitting a bonus level instead (ignore the hearts on this screenshot – it was taken during the Valentine’s event):
Once you hit the bonus levels, you get a choice of three boxes containing 1,2 or 3 donuts – and you can read about what happens here. But once you’ve passed the bonus level, your XP bar turns pink and drops back to the beginning again, as you can see in this screenshot:
The first time it happens, it can be disconcerting. But it doesn’t mean you’re back to the beginning of level 26 again. It just means you’re building towards a new bonus level. And, hidden behind the scenes, your blue XP bar is full and waiting for the release of the next level.
So, what will happen when level 27 comes out? You’ll be pleased to know that your XP bar will automatically turn blue again, no matter how much of the pink bar has been filled up. You’re also likely to have a head start on your XP (when level 26 was released it was around 10,100) and you’ll be heading towards the bonus levels again. And that’s where you’ll stay until level 28 is released.