What's the oldest iPhone you guys still use as a phone?

^title.
I use the iPhone 5C, before, I was using the iPhone 4 (.5 year ago). I want to know what old iPhone you're still using.

I still have a sumsung flip phone!

IPhone 4s. I don't use Iphones but I know few people that that would be the oldest phone people StI'll use. I have an android. Galaxy note 3

S III

I had 3GS last year, replaced it with iphone 5S

Galaxy SII, still works amazingly. I also have a Kyocera Event which is the worst phone ever, it's impossible to go on the internet without it freezing.

I use the 5s right now. Prior to this I was using a 5c, which isn't any older I believe.