Does the new Premium account work with Volumio 2?

This may be a stupid question, since support hasn’t responded to my email for two days… Never mind, I’ll try here: I have two devices which I use with Volumio and switching MyVolumio on/off between them is a bit inconvenient. One of the devices is a Sparky, which did not receive Volumio 3. My question is: if I upgrade from Virtuoso to Premium on my Volumio 3 device, will this work on my Volumio 2 device as well?

For me, this is the sole reason for upgrading - so before I say goodbye to my Virtuoso account for ever, I would like to have some confirmation…

The best solution for your scenario is that you upgrade to Superstar from your Volumio 2.X device.
This way you can use multiple devices of Volumio 2 and 3 together.