I have 3.1.10 and have paid for and downloaded Dorico 3.5 with the Steinberg download assistant.
The new version has been opened and installed but when I open Dorico it doesn’t ask for the activation code but opens in 3.1.
I am sure I’ve forgotten an important step but can’t figure out what it is.
If you are on a Mac, the OS doesn’t always replace the old desktop icon with a new one; you have to find version 3.5 in the Finder and update the icon yourself. On Windows there should be both the 3.0 and 3.5 on your desktop after installation. IIRC clicking on a Dorico doc will take you to the older version.
It sounds like the shortcut on your desktop must be for Dorico 3.1, and that’s what you’re running. If all else fails, go to C:\Program Files\Steinberg\Dorico 3.5 and run Dorico from there.
There are different licenses for Dorico 3 and Dorico 3.5, and you can use both on the same computer (but not at the same time).
Deleting the license for Dorico 3 won’t delete the application or change how your shortcuts to launch programs work. It just means that you can’t do anything when you try to open it.
To be clear, if you update to Dorico Pro 3.5, your existing Dorico Pro 3 license will be “consumed” by the update process, so you will no longer have a license for Dorico Pro 3, but your Dorico Pro 3.5 license will allow Dorico 3 and all previous versions of Dorico to run on your computer in case you need to keep using them.