The "col" class does not work in mobile browsers, what is the reason?

Question

Layout

It is necessary to make 8 columns, I use bootstrap 4, the code is div.row>div.col*8
Everything works as it should in the browser, everything is fine in the development tools in the mobile browser, but in safari, firefox on iPhone 5 everything is in one line . Help me to understand.
The viewport tag is present.

Answer 1

Who is to blame: On mobile devices, the browser version depends on the OS, so on the 5th there is an old safari that coughs from flexbox.
What to do: use prefixes or arrange a promotion "come to us from the old ios and get shit on the page"