Not fully supported anything below IE11 since january. Surprisingly very few questions, negative feedback or negative impact on site traffic. Just pure joy at work. "Caniuse? - Yes, you can use."

We do 9, since it supports media queries.
A shiv, and a pseudo plugin... Good to go.
I am honestly at the point with my less framework, that I barely even look at my work in IE ... I just assume it works as long as I exclude form elements in my styling for IE. That shit never works well.

Anybody else going further back?

@lewdogg We go down as low as 8 since our customers are still active to that far. However we don't completely support it. Like CSS stuff like rounded corners and such we don't bother with. And the front end code just mostly works just because of shims and prototype additions. So overall we rarely have to do much to make it supported. After this summer we plan to phase it out to 9 though.

we do 9 but to be honest, I don't check and I don't get complaints

Our company policy is IE9 and later right now, even though Microsoft is dumping 8, 9, and 10. I've voiced this multiple times to PMs who don't give a shit and ask me to fix the missing text shadow as if it's the end of the world 😑

Oh yeah, our statements of work clearly say 9 and up. Which are signed and approved. But always get the PMs demanding that I fix the IE 8 bugs that were submitted, stating "we told them this would work" ... Uh ... No ... No, we didn't.

We flat out don't support IE, when we sell our product we say Firefox or Google chrome are the only supported browsers. But as our app is only accessible within the companies local network this is less of an issue