Is the firmware of Osmo Mobile 6 compatible with DJI OM 5?

No. However, the DJI Mimo app will provide the correct firmware version once connected.

Related Questions

How should I set up the DJI Osmo Adjustable Quick Release Adapter Mount when using the invisible selfie stick feature?

Set the adapter to the 0° position to align the selfie stick and camera horizontally for optimal results.

Which app is used with DJI Air 3 and where can I download it?

Where can I download the DJI Fly app?