While we are on the topic of unpopular support changes, let's continue with Internet Explorer. 🙂

Internet Explorer 10 hasn't been receiving security updates since January 12, 2016 (source) and using it to access the internet is highly dangerous. In addition IE 10 never was really popular and seems to be only be used by 0.07%.
Therefore I think it is really easy to completely drop support for IE 10 in Matomo 4.

Personally I would like to also drop IE 11 and only support Edge, but I guess this won't be feasible as far to many companies are using it and don't have another way to access Matomo.
In addition IE 11 still receives security updates (but unfortunately no bug fixes anymore).
Funfact:

Internet Explorer 11 will be supported for the life of Windows 7, Windows 8.1, and Windows 10.
https://www.microsoft.com/en-us/windowsforbusiness/end-of-ie-support

As Microsoft doesn't seem to be planning to release an update that isn't called Windows 10, IE 11 will probably be supported for eternity 🙂 .

Note: This does not mean IE 10 users won't be tracked anymore. The tracking script will continue to support ancient browsers. (Although it might be worth it to move the definition of "ancient" to IE7+ #6093 (comment))