Update browser support

[mdo]

I'd like to be more aggressive in our browser support—this is a first pass at it. Looking at our compiled CSS, we've added a ton. 😭 This list has largely been out of date aside from the dropping of IE9/10. I'm thinking about this because of the number of flex properties that require vendor prefixing—it literally triples line of flex code you write. This knocks down some of it.

[mdo]

Fwiw, worst case scenario after merging something like this is that we have to support older browsers, which isn't a breaking change. On the flip side, wanting to drop older browsers is a breaking change.

[yasinkocak]

Drop older browsers

[Johann-S]

We are still in Alpha so breaking changes it's something which can happen, I'm in favor of dropping old browsers, maybe you'll find interesting information here : http://caniuse.com/#feat=flexbox

[lorvent]

eventhough i love dropping support for old browsers for obvious reasons,
we develop products and customers with old browsers will cry now.... (i really hope everyone ditches IE and moves to firefox/chrome)

[PascalPixel]

To summarise caniuse as @Johann-S stated: 12.29% of current active internet users do not have working flexbox support, including the entire Indian subcontinent

[mustafa-online]

Supporting old browsers is a good thing in some aspects, especially Flex property, because it is the core of the framework now 😃

[mdo]

v3 will handle all the older browsers out there if you need to support them. We'll get a v3 quality of life update out after v4 ships. That's always been the plan :).

[andrerom]

@mdo Based on both browsers support and usage data in http://caniuse.com/#feat=flexbox, and considering the two years that has passed since alpha 1. Shouldn't this rather bump Explorer >= 11 and Edge >= 14 for the beta?

[Herst]

@andrerom #21416 was when the decision for dropping IE9 but not IE10 was made. @mdo said in that thread that supporting IE10 hasn't been an issue at all.