The June 2020 Product Terms contains an amendment to the definition of Firstline Worker devices. A Firstline Worker is typically someone whose job is primarily based away from a PC – think construction worker or doctor – but they do need some access to technology.
Rules for assigning Office 365 F3 and Microsoft 365 F1/F3 licences (the Firstline Worker plans) are based on the user’s primary device. Prior to June 2020, a Firstline Worker was not allowed to have a Dedicated Device – a computing device with a screen of 10.1″ or larger used by the user for more than 60% of their total work time in any 90-day period.
It’s simpler from June 2020 – the user’s primary device must have a single screen smaller than 10.1″ OR they must share their primary device with other qualifying Firstline Workers.
Find the rules on page 58 of the June 2020 Product Terms and find the Product Terms document itself here: http://bit.ly/MSproductterms.