Currently i use the latest eM Client mobile iOS iPAD app V10.3.2242 with a Logitech Pebble Keys 2 Bluetooth external keyboard with IPad OS 18.5
The up and down arrow keys “do work when you are inside an email” within eM Client mobile app to scroll up and down, but just don’t work when trying to navigate up and down the email subjects.
Yes you can use the Logitech Bluetooth Mouse to scroll up and down through the email subjects using the scroll wheel, but would prefer to also use the Keyboard arrow keys.
Note: The up and down arrow keys do work on the eM Client Forum using eg: Chrome mobile browser. So sounds like the mobile app needs an update / fix.