Was it a safe to drink this expired pop (soda)?

I’m not terribly worried about this. Mostly just curious. I bought some Code Red (Mountain Dew) 20oz. back in August for the late night studying. I went to open one day, and noticed some sort of orangish precipitate at the bottom of the bottle. I swirled the bottle and it partially dissolved. Apparently it expired in October (which is a surprisingly short time after I bought it). I, of course, decided to drink it anyway.

Just wondering if soda actually goes bad, besides going flat?