Welcome to FlyerTalk, jetlikesdimsum!

There probably is a reason why the original flt was changed. But whatever, you could always call DL and ask for 2242 instead if this was a recent change (you don't want to get hit with a change fee).

That said, most of my t-con flts from the west coast to ATL arrive early and I have made 35-min connections in ATL a few times. You should be quite fine with what you have unless you run into some serious winter weather issues.