[civilian]

This is absolutely a failure of management. Both the general management and _especially_ the engineering management.

Eng management needs to convey that this is an Achilles' heel that is important to understand & be able to update.

No engs want to work on perl5? Bribe existing employees, hire someone who wants to work on perl5, or a darker third option.

The product owner can even spin this as them doing a good thing to future-proof the business, even if it means their team loses velocity on other projects.