All bootstrap breakpoints deprecated?
Solution 1:
What @seven-phases-max said. The @screen-{sm,md,lg}-min variables are the ones you should use. The others have been deprecated in favor of these.
And @screen-xs-min is deprecated because XS has no narrowest screen size (unless you want to count 1px) since it's the smallest breakpoint. (Likewise, LG has no maximum width.)