Compatibility Mode gets triggered in IE8

[mstorus]

This is a tough issue to reproduce consistently, but FontAwesome will often cause IE8 to fall into Compatibility Mode.

I can reproduce by visiting http://fortawesome.github.io/Font-Awesome/icons/ in IE8 and then hard-refreshing the page. Sometimes clicking on a font and then hitting the back button will trigger it too.

I have also seen this IE8 compatibility mode issue with a custom font that is also using the Unicode Private Use Area (PUA), so I suspect it might have something to do with the unicode mapping of the glyphs.

Here are a couple articles that discuss the issue that might be useful.
http://adactio.com/journal/6555/
http://www.clockwork.net/blog/2013/10/08/657/how_to_avoid_forced_compatibility_mode_in_ie8_and_keep_your_custom_fonts

However, I'm not convinced that the Latin range fix will work, because in my testing with a custom font, it didn't solve the issue for me.

[tagliala]

Is the font using Private Use Area characters? Can they be changed to use Basic Latin? If so, make the change to basic Latin and try again. You may find the compatibility mode issue is solved.

FA uses the PUA by design

Moreover, IE8 has random issues with pseudoelement. Leaving this open but I'm not confident that dave will switch to basic latin

[Sophist-UK]

The clockwork.net link suggests that adding a meta tag to the HTML head might prevent IE8 from flipping intoi compatibility mode.

Obviously FA cannot do this itself - it is down to the template designer or webmaster to do this.

[tagliala]

Fixed docs and added this info to troubleshooting guide, thanks!

https://github.com/FortAwesome/Font-Awesome/wiki/Troubleshooting#internet-explorer-compatibility-mode

[mstorus]

I don't think this really addresses the issue. IE8 goes into compatibility mode because it has some kind of problem rendering the font in Edge mode. If you force it to use Edge mode with the meta tag, now it will just crash completely instead of going into compatibility mode.

[tagliala]

@mstorus sorry but we can't deal with IE8 random bugs.

Since bootstrap's default template include that meta tag, that's fine to have it in FA documentation

https://github.com/twbs/bootstrap/blob/master/docs/_includes/getting-started/template.html#L12

[simon-online]

The proposed solution for this on the Troubleshooting page didn't fix the issue for me with FA v4.4.

Here's a solution I've posted on SO which completely fixes this issue for me:
http://stackoverflow.com/a/33162245/4387229

[mstorus]

The root of the problem seemed to be the use of the PUA range in IE8.
The only solutions that always work for me are to choose a different unicode range to assign the glyphs to.
I wrote this answer http://stackoverflow.com/a/29441642/598093
After a lot of experimentation, I found that the Low Surrogates Range appears to work without issues in IE8.