Can't upgrade Logitech unify Firmware using fwupd

I tested all (probably most) of the solutions that are online. And the solution that worked (I'm using Ubuntu 18.04 Live) is the following:

1. Remove the apt version of fwupd with

    sudo apt remove fwupd
   

   Because the current repository version of Ubuntu 18.04 seems to be

   client version: 1.0.9
   checkout info: 1.0.9

   This is a problem, because this version yields the following error:

   cannot handle firmware requirement not-child

2. Replace it with the snap version of fwupd which also (maybe) installs snap, too.

    sudo snap install fwupd --classic
   

   The current snap version on the other hand provides a newer version which works without this complication. Its version is (as of July 2019)

   client version: 1.2.10
   checkout info: 1.2.10

   As of June 2020, the following is valid

   client version: 1.4.3
   daemon version: 1.4.3

3. With this current version, execute

    fwupdmgr refresh
   

4. And finally, execute the update

    fwupdmgr update
   

5. Now test the version with

    fwupdmgr get-devices | grep -A30 "Unifying Receiver" | grep -i "version:"
   

   Its output should be (as of 15th May 2021):

   Current version: RQR12.10_B0032

As suggested here the problem is most likely caused by the version of fwupd being too old and no longer supported. The fix, suggested both on that issue and here is to boot from a live media with a newer version of fwupd and to upgrade using that version. Please see the latter answer for details on how to do that.

[Later Edit]: Even though I tried the above with Ubuntu 18.04 and it updated successfully, after booting back to Ubuntu 16.04 the update was still showing up. I eventually updated the firmware via a Windows machine and the software from here. I am not certain that that is the latest version (as the software did not report the firmware version) but the Ubuntu update did disappear afterwards.

For me these commands worked

   sudo apt remove fwupd

   sudo snap install fwupd --classic

   sudo fwupdmgr refresh

   fwupdmgr update

   sudo fwupdmgr -v update (mouse on)