Help -> Check for updates is empty.
I have selected: Oracle SQL Devloper, Oracle Extensions and Third Party SQL Developer extensions.
When I click Next, it is empty. There isn't a error reported and I haven't configured any proxy or vpn.
I have to install jdbc drivers database via Tools->Preferences, becuase anything is displayed in check for updates.
I have just update to 20.4.1.407 (with a 20.2.x version happened to me the same).
I attach the url configured for extensions, etc:
sql-developer.PNG (7.81 KB)