TechRadar was sent a small safe - yeah, you read that right - where if you enter today's date (0908) it opens and reveals a teaser for the battery on whatever phone is coming next.
Pictured are two devices with 4000mAh cells, alongside one with a 3750mAh cell and the last diagram then suggests the battery will be bigger on the upcoming phone.
That last image on the right is actually printed onto a portable battery pack, which again is 4000mAh. That doesn't give us any evidence of how big the battery is considering the diagram suggests it'll be bigger than that.
There's no word on the name of the phone or how much bigger the battery will be, but the fact we're getting teasers about it already suggests we may be nearing a launch for the Mate 20 Pro.
The timeline at the bottom of the teaser shows how the Mate 10 series was announced in October last year, so it may be the company is aiming for an October launch again this year or perhaps we'll hear about it sooner than that.