AngularJS 1.3 and IE8
I have Angular 1.3 working with IE8.
It requires jQuery, a couple of shims and one source code change to Angular. I'm maintaining builds of Angular with a lot of the shims baked in and instructions on what else to include here:https://github.com/fergaldoyle/angular.js-ie8-builds
I can't get the unit tests running properly with IE8 so can't confirm 100% compatibility, but using a broad smoke test I can confirm every feature I've ever used with Angular works fine in IE8 + 1.3
It simply means that they've stopped testing for anything beyond 1.2.x, which enables them to "add more exciting features to Angular faster, decrease Angular's support burden, and cut [their] build time in half, while affecting only a very small proportion of users."
They're not necessarily removing the hacks from Angular that made IE8 work but there's no guarantee that changes in anything after 1.2.x won't break an application running on IE8 since they've stopped supporting it and addressing any issues that are solely related to it.
The above was what they said in a post about a year ago, so it might very well be the case that there are certain features that break today. With that said, your safest bet would be to work with 1.2.x, unless you want to use 1.3.x and test it yourself.
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After trying it on my own - no, Angular 1.3 simply won't run on IE8. It's not a matter of shims, or other libraries, or some hacks. It just won't work at all.