You should be registered on 2020.net – try logging in there. Once logged in, go to Support Download and current supported versions are there. If you have no 2020.net login, here is the link to V11.8: http://cdn.2020spaces.com/support/Design/V11/Versions/11.8.0.53-Both.exe
If you have purchased V11 within the last 12 months, you will be on support and should be able to run the new version. If you purchased V11 before this, you should check to see if you have paid your annual support and maintenance fees – if you haven’t then you won’t be able to upgrade to the latest version (this is normal for all software).
When you upgrade, I recommend performing a Basic Uninstall (one of the tick box options) of your current version before installing the new version – this will leave your catalogues and settings in place. I do recommend that you download my Settings Saver script from an earlier post and run this before uninstalling just in case.
When doing any form of uninstall/re-install, your design files will be left alone.
Hope this helps
Mike