Quick question on operating systems

Hello,

I tested Pianoteq recently, and it was up to my expectations. So I'm thinking of buying it.

I had to indicate my operating system when I downloaded the demo, so I assume it will be the same if I buy the full version.

My question is : if I buy and download a version for a given OS (let's say Windows), will I be able to change it when I switch to another (let's say Linux) ? And again if I choose to go back ? And what if I get a Mac some day ?

Thanks !