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 03.10.2020):

   Current version: RQR12.10_B0032