The below information is for your attention!
Mendeley Reference Manager is the new version that replaced Mendeley Web Library on September 07, 2020. Mendeley Desktop is still available for use and can be downloaded here.
When will Mendeley Desktop stop being available?
When Mendeley Reference Manager meets the users' reference management needs, Mendeley will begin the migration process by notifying users via emails and other forms of communication.
To migrate over to the new Mendeley Reference Manager, you will need to make sure you have synced your current Mendeley Desktop and then download the new Mendeley Reference Manager. Having synced your Desktop, all of your work will then exist in the new Mendeley Reference Manager.
Source: Mendeley Support