It might be worth exploring the feasibility of having an online vi upgrade/downgrade service, where you could submit your vi, and receive back the new vi.
I realize this wold be a huge undertaking, however, a reasonable fee could be charged. It could be a second option, in case the customer:
Has tried to do this on their own and failed
Does not have the intermediate versions to perform the required jumps
Isn't worth their time considering the cost of the service
In the case of upgrading a vi, this could serve as an added incentive to invest in the latest version of Labview, especially if the customer is several versions behind.
Duplicate of https://forums.ni.com/t5/LabVIEW-Idea-Exchange/VI-conversion-WebService/idi-p/2119238