According to new reports, Samsung has altered the Galaxy Z Fold form factor for this year's model. Reputedly, the Galaxy Z Fold4 will have a shorter cover display than the Galaxy Z Fold3, along with a squarer foldable display.
https://www.notebookcheck.net/Samsung-Galaxy-Z-Fold4-New-leak-highlights-display-changes-from-the-Galaxy-Z-Fold3.618415.0.html