Upgrade to springboot 3
At some point we will want to upgrade to SpringBoot 3. Springboot 2.7 (the prior version) is technically already out of support ( https://spring.io/blog/2023/11/23/spring-boot-2-7-18-available-now ) though in practice it's likely to continue to receive fixes for CVEs for the length of the commercial support I believe: https://spring.io/projects/spring-boot#support - i.e. till August 2025 )
There's a component in springboot 2.7 that we use that is deprecated and I think is removed in springboot 3, so we need to switch away from that either before or during the upgrade to 3 as was mentioned in #1248 (closed)
The problem in particular is org.mitre openid-connect-client
which I understand just doesn't work with springboot 3.
We had some previous discussions about approaches to solving that in this google doc: https://docs.google.com/document/d/1cgRQgQrwRr38AgUhabhyHPq75xl2DGcv/edit (which is a little old/out of date now as it implies we couldn't upgrade even to springboot 2.7 without these changes, but that did prove to be possible)