The Galaxy Z Fold 4 and Galaxy Z Flip 4 are rated IPX8, meaning they're as water resistant as other flagship phones, but have no guaranteed protection against small particles entering the device, and potentially damaging the inner components. IP58 means instead that, as well as being waterproof up to 1 meter, the phones would be "dust protected", meaning while dust could still enter the phone, it, in theory, wouldn't cause any problems for using the device.
For comparison, the best phones, such as Samsung's own Galaxy S23 series, are rated IP68. The enhanced dust rating here guarantees no entry of dust into the device.
Samsung's IPX8 rating for its foldables is already an improvement on most other foldable phones, which have no official protection against water and dust. Adding dust protection would increase Samsung's lead further, which is crucial now that competitors such as the Google Pixel Fold and the rumored OnePlus V Fold are starting to emerge.
A new hinge with new problems
However, these upgrades could reduce the effectiveness of Samsung's Flex Mode, according to leaker Revegnus. This is the feature that allows the Z Fold and Z Flip to be partially opened without the phone snapping fully open or shut, handy for standing the phone up to take photos or watch videos.
Revegnus blames this on changes in the hinge's design (possibly making the crease shallower) and weight, including to its waterproofing. These are all aspects worthy of upgrades, particularly if it also means a less obvious crease in the display, but it would be a shame if it came at the expense of one of the Z Fold and Z Flip's unique features.
At least, according to different leaks, we can expect more straightforward upgrades like a larger cover display on the Galaxy Z Flip 5, and a new chipset for both phones. It appears that the Galaxy Z Fold 5 will be a minor upgrade over the Z Fold 4 compared to what the Z Flip 5 changes from the Z Flip 4.
Samsung's now announced a launch event for new foldables towards the end of July, so it feels like it won't be too long until we get to check out what exactly Samsung's done with its next-gen foldables.