Below is a step by step guide on how to use your perpetual fallback version of your JetBrains product.
In order to use your perpetual fallback version, you will need to uninstall the newer version and install your perpetual fallback version.
1. To check fallback which fallback version you currently have, log in to your JetBrains account.
2. You will see your Fallback license(s) within your JetBrains account page. The fallback version is in blue and below the line ‘Licensed To.’ See the attached screenshot.
3. Download your fallback version by clicking on the designated version within your account page, or you may visit the previous version page listed below for your appropriate fallback license:
IntelliJ IDEA Ultimate: https://www.jetbrains.com/idea/download/previous.html
.Net and Visual Studios
ReSharper, includes ReSharper C++, dotCover, dotMemory, dotPeek, dotTrace: https://www.jetbrains.com/resharper/download/previous.html
4. After downloading your designated fallback license, register your fallback product using either your JetBrains account credentials (username/email and password), offline activation code, or license key.