Yeah, from personal experience any time I or anybody else tries to argue that supporting IE isn’t worth it any more, a PM will pull out traffic statistics and say ‘see, x% is still on IE, we can’t not support them’
[1] https://techcommunity.microsoft.com/t5/windows-it-pro-blog/i...
[2] https://docs.microsoft.com/en-us/lifecycle/announcements/int...
Sure, which can be countered with: "no problem, it will add 30% to the estimate".
Unless the % is significant (over 10%), it's not worth the effort.
One day Safari will enable smooth scroll.
Also don’t forget to check actual conversion and other important metrics for different browsers, not only number of visits.
And the school site has quite an active userbase - students upload assignments via it, parents can live-view all gradings and remarks (and regularly use it), and staff generally access their email via it instead of a client.