Spring Security Upgrade & Custom TokenStore

I'm seeking an experienced developer to assist with the upgrade of my project's security framework. The project is currently using an archived version of Spring Security OAuth, and I need to transition to the latest Spring Security 6.x.

Key Tasks:
- Upgrade to Spring Security 6.3.4
- Recreate the InMemoryTokenStore with specific customizations
- Transition from XML to Java configurations

The ideal candidate will have:
- Extensive experience with Spring Security
- Proven track record in Java configuration
- Ability to implement and customize a TokenStore
- Strong understanding of token encryption and expiry control

Specific customizations for the TokenStore will involve including custom token attributes.

Please note, the current TokenStore implementation in use is the InMemoryTokenStore. I'm ready to discuss the specifics of the customizations needed, so prior experience with creating custom token attributes will be beneficial.