When you pair the keypad, if the DTH is installed correctly, the DTH will be automatically selected for the keypad, no need to manually select it.
It’s possible to do a firmware update using an Iris hub, but as far as I know, the only firmware update available is just a fix for battery life (There’s an issue with older firmwares where the lights stick on). Shouldn’t affect the pairing at all.
Since you’re not getting anything in the Updated: field, I’d more suspect that the keypad isn’t fully paired. This keypad has a 2 stage pairing, one to get it onto the Zigbee network, via “Add thing”, then the Zigbee alarm enrollment, when it sounds like isn’t complete.
If it’s on the network, but not enrolled as an alarm zone, it’ll report temperature and battery life, but won’t get status info, won’t send PIN / arming data, and won’t ack the arming/delay tones.
I’d suggest you remove the keypad from SmartThings, factory default the keypad, then re-pair.
After the factory default, they keypad should go into pairing mode (slow double-blink of the network light on the front). Once it’s paired to SmartThings (via the SmartThings add thing button), the network light should blink quickly, continuously.
At this point, you need to press and release the tamper switch on the back of the unit, to attempt to enroll it for alarm functions. I tend to press the button twice, for good measure, then wait 2-3 minutes, until the keypad beeps, or the network light goes on solid (It’ll only be on when the keypad is lit via motion). After the beep, and the network light is on solid, arming, disarming, and the entry/exit beeps should work.