HTC has promised relatively speedy Marshmallow updates for the flagship One devices, but that's not as simple as flipping a switch. Even when the goods are ready to go, the company still must get the software out to numerous variants running in different countries across the world.

Everyone has to wait their turn. Next in line are HTC One M8 owners in the United Kingdom. The HTC UK Twitter account has sent out word that the Android 6.0 update is coming to the device over the next 48 hours.

Interestingly, the M9 is set to get the update sometime shortly thereafter. That means last year's flagship will get the latest version of Android before this year's in the UK. This also matches the pattern we saw last month here in the US.