Hello Jonas,
You can have both.
You already copied / paste the folder and renamed it to DS 1.5, and installed 1.6 after right ?
You right as well: you will need 2 sets of analyze-workspace and analyze-config.
If you have both right now installed, just remove the folder (or rename etc ...).
Start 1.5: it will creates the folder again. Configure DS, close, and save the folders somewhere.
Do the same with 1.6.
When you need to start either 1.6 or 1.5, simply rename or copy/paste the 2 folders according to your version.
Also, avoid starting DS by any other method than by the executable. Sometime, restarting DS when prompted use the most up to date version and upgraded the folders ...