The capablities of jD3.9 and jD4.0 series are fundamentally the same but the screen views and how to access items are often a little different.
Each Document has the date of its latest version after the main title. For Example: "Upgrading from jD3.9 to jD4 -November 2024"
Despite apparances, the date part, such as  -November 2024, is not included in any links or similar.