Lufthansa 737 Over Canada (D-ABXX)

Currently airborne, taking the long way across via KEF & YYR

Is this a retirement flight?

A good bet. I was at KTUL some number of months ago. Far side of the field has a Lufthansa Technik facility. There was the carcasses of a couple of LH 73’s, an ANA A320 and a freshly flown in LH 747-400.