Microsoft announce some changes to their plans for Firstline Workers, effective from 1 April, 2020. The existing Microsoft 365 F1 plan will be renamed to Microsoft 365 F3 and keep its $10 per user per month price, and a new plan (with a lesser set of functionality) will take the Microsoft 365 F1 name and have a price tag of $4 per user per month. Office 365 F1 is also renamed to Office 365 F3 and remains at $4 per user per month. All of the Firstline Worker plans will have additional  Teams functionality added, as well as enhanced identity and access management features.

There’s a useful chart comparing what’s available in the different plans in the announcement article here: https://bit.ly/3a6Qkg4.