How many latest browser versions do you support?

Question

Cross browser

It's about:

autoprefixer({browsers: ['last 5 version']}),

Not strong in browsers, for example, I have Chrome 56.0.2924.87 then 5 versions ago will be Chrome 51? This is approximately what time, a year ago, 2 years ago?

Answer 1

So here's https://www.npmjs.com/package/bootstrap-sass
To match upstream Bootstrap's level of browser compatibility, set Autoprefixer's browsers option to:

[
  "Android 2.3",
  "Android >= 4",
  "Chrome >= 20",
  "Firefox >= 24",
  "Explorer >= 8",
  "iOS >= 6",
  "Opera >= 12",
  "Safari >= 6"
]

Answer 2

If prefixing is automated, I see no reason not to put the maximum.
This business does not take a lot of bytes. +1% to current code size.

Answer 3

The latest versions of browsers or at the request of the customer.