For a new WordPress website, Divi 5 is generally the better choice than Divi 4. Divi 5 is the newer platform and is designed to provide a faster, more modern foundation for building websites with improved layout controls, responsive design options, and a more flexible visual editing experience. Divi 4 can still make sense when an existing project depends on older third-party plugins, modules, or established workflows that have not fully transitioned to Divi 5.
If you are starting a website from scratch, there is also little advantage to choosing Divi 4 simply because you are familiar with it. Instead, look for Divi 5 Themes, Divi child themes, and Divi Layouts that specifically support Divi 5. Resources from providers such as Divi Hat can give designers ready-made layouts, wireframes, and child themes to use as a starting point rather than designing every page from scratch.
Before choosing a Divi 5 Theme or layout pack, check whether it was built specifically for Divi 5 or merely made compatible with it. This is particularly important for client websites that rely on third-party plugins or custom modules.
For existing Divi 4 websites, migration requires more planning. Test the site on staging, back up the website, and verify that essential plugins and custom functionality work correctly before moving to Divi 5.