I've worked on several projects where we ended up having to crack that kind of protection - often, with the formal written blessing of the license owners, who w

I've worked on several projects where we ended up having to crack that kind of protection - often, with the formal written blessing of the license owners, who were happy to continue to support our use but did not have the ability, resource, or sometimes, even the source code to the product anymore. This may be an option for your customer if they haven't tried it already. Sometimes a few hours of highly skilled RE work, even if you have to contract it out, can pay huge dividends in preventing downtime due to having to source antiquated hardware combinations or maintain broken software. We were even able to move some ancient, unreliable, insecure airgapped Windows 2000 server hardware into Windows Server on AWS where we could back it up, monitor it, and provide high availability and remote access. In my experience this can be the happy medium between "it's working, don't touch it" and "WTF this runs on DOS and the 30 year old machines break all the time"