According to reports, Samsung will be making at least two modest improvements with this year's Galaxy Z Flip. Not only will the Galaxy Z Flip4 feature a larger battery than the Galaxy Z Flip3, but also a more spacious cover display. Purportedly, Samsung has decided to upgrade the Galaxy Z Flip to over a 2-inch cover display, which should deliver an improved user experience over the equivalent in the Galaxy Z Flip3.
https://www.notebookcheck.net/Samsung-Galaxy-Z-Flip4-Talk-of-a-larger-cover-display-emerges-for-next-generation-Galaxy-Z-Flip-smartphone.616935.0.html