StaffHiya, welcome to the community.
I have also replied on reddit, but have copied my reply here as well.
Swagger Parser 2.1.23 is a 2 year old release.
https://github.com/swagger-api/swagger-parser/releases/tag/v2.1.23
Going by the docs, Swagger Parser 2.1.0+ supports OpenAPI 3.1 with Swagger Parser 1.x line having support for Swagger 1.0 / OpenAPI 2.0.
We are working on the Jackson 3 upgrade across the ecosystem, but most likely won't be back-porting to the 1.x swagger parser line. We have accepted PR's to this branch, so I would recommend testing out your solution in a fork, and proposing the changes back, however I would also raise the issue on the GitHub repository, as you may get community support from others.
Can you confirm where in the documentation or code, it shows that there is Swagger Spec 1.x compat in Swagger Parser 2.x line?
