I'd say calibration is just "good practice" when removing and reinstalling the airbags in the suspension, certainly not required though.

Many shops I'm sure change the X5's air bags and don't think twice about performing a ride height calibration afterwards.

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2018 Ram 2500 6.7L Cummins 68RFE
19k miles -Bright White/Black - Big Horn Sport - Crew Cab Short Bed
2013 X5 35D (CEO's) - Born on 5/17/2013 -
82k miles - Alpine White/Cinnamon Brown/Premium Pkg, Sport Activity/Premium Pkg and Sound/20" Style 214/Running Boards