The updated iPadOS 13.4 is to be released on March 24, and will support both Apple's new Magic Keyboard with Trackpad, and third-party mice across most recent iPad models.
The new iPadOS 13.4 includes an updated Measure app that takes advantage of the depth-sensing LiDAR scanner
Alongside the release of the 2020 iPad Pro models, Apple has announced that an updated iPadOS 13.4 will be available from March 24. The new iPadOS, which will come pre-installed on the new devices, brings the anticipated full support for Bluetooth and USB trackpads or mice.
Previously, trackpads and mice were officially supported only by way of an iPadOS accessibility feature, which had limited functionality. Now dragging a mouse, or dragging across a trackpad, will turn the cursor into a circle which highlights what's dragged over.
How the new trackpad support looks in iPadOS 13.4. (L) dragging over a text box, (Middle) selects it, and (R) dragging on to the next box selects that instead
The new iPadOS 13.4 will work with all iPad Pro models, the iPad Air 2 or later, iPad fifth generation or later, and iPad mini 4 or later.
Apple confirms that iPadOS 13.4 works with the Apple Magic Mouse 2, Magic Trackpad 2, and also the forthcoming Magic Keyboard for iPad Pro. It will also support third-party mice that are connected over Bluetooth or USB.