Unscrew the three bolts in the plastic endbell, and then carefully pull the old probe head off. Sometimes some gentle side-to-side rocking (carefully – work slowly) is needed to loosen the O-ring seal. The new head will attach the same way as the old one, and the three-bolt pattern should ensure there is only one way for it to be attached. Once the new head is seated in place, screw in the three bolts so they are snug (don’t overtighten them). There is no need to change the firmware.
After all that you should be good to go. We recommend you to do a probe check to verify everything is working.