Sony WH-1000XM4 and WF-1000XM4 Firmware Update

I was not expecting to be creating a firmware update post for the WH-1000XM4 or WF-1000XM4, but here we are. Both models have the same update:

• Enhanced the security features of the system software

A similar security update is also present in the recent WH-1000XM5 update, so not sure what this is pertaining to. The WF-1000XM5 does not have this in its recent update change log, so I am puzzled as what this could be for. The mark 5 earbuds did not have any such security update in the past either, so either this update is already included in the firmware, or not required.

Anyone have any ideas why such a security update would be required for? I do not think it is related to the new Sound Connect app, as other models like the WF-C500 or WF-C700N have no such update and still work with the app.