To find out which version of Monument Valley is running on your mobile device, simply click on the top left side icon on your screen.
You will find the game version at the very bottom of the page which just opened.
It'll look like this: 2.5.18
This information can be quite useful for us if you encounter a technical issue with Monument Valley. So don't hesitate to include it in your message when you reach out to us.
We hope this helped. :)