[FEATURE] Training data gap: Spring Boot 4 is not covered (released Nov 20, 2025)

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Spring Boot 4.0.0 was released on November 20, 2025, three months after
Claude's training cutoff (August 2025). Claude is unaware this version exists
and gives incorrect guidance to developers working on Spring Boot 4.x projects,
including wrong patterns, removed APIs, and missing new features.

Proposed Solution

Include Spring Boot 4.0 and Spring Boot 4.1 (currently in RC) documentation,
release notes, and migration guides in Claude's training data, covering:

• Spring Framework 7 as the new foundation
• Java 17 minimum / Java 25 first-class support
• Jackson 3.0 migration (new group ID: tools.jackson)
• @MockitoBean / @MockitoSpyBean replacing @MockBean / @SpyBean
• Undertow removal (incompatible with Servlet 6.1)
• Built-in API Versioning (spring.mvc.apiversion.*)
• HTTP Service Clients auto-configuration
• New OpenTelemetry starter (spring-boot-starter-opentelemetry)
• Complete modularization of Spring Boot jars

Alternative Solutions

Provide an updated knowledge cutoff date per technology/framework so users
know when Claude's knowledge ends for a specific ecosystem.

Priority

Medium - Would be very helpful

Feature Category

API and model interactions

Use Case Example

A developer asks Claude to help migrate a Spring Boot 3.x project to 4.0.
Claude incorrectly states that @MockBean is still valid and that Undertow is
a supported embedded server, leading to broken builds and wasted debugging time.

Additional Context

• Official announcement:

https://spring.io/blog/2025/11/20/spring-boot-4-0-0-available-now

• Migration Guide:

https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-4.0-Migration-Guide

• 4.0 Release Notes:

https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-4.0-Release-Notes

• 4.1 Release Notes:

https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-4.1-Release-Notes

• Model: claude-sonnet-4-6
• Claude's stated knowledge cutoff: August 2025
• Spring Boot 4.0.0 release date: November 20, 2025

Breaking changes Claude is unaware of include (but are not limited to):

Renamed configuration properties:

• spring.web.error.include-message → (renamed in 4.0)
• spring.session.redis. → spring.session.data.redis.
• spring.data.mongodb. → spring.mongodb.

Renamed/removed annotations:

• @MockBean → @MockitoBean
• @SpyBean → @MockitoSpyBean

Dependency group ID changes:

• Jackson 2.x (com.fasterxml.jackson) → Jackson 3.x (tools.jackson)
• Elasticsearch RestClient → Rest5Client

Removed modules:

• Undertow (incompatible with Servlet 6.1)
• Pulsar Reactive
• Spring Session Hazelcast and MongoDB

Etc..

These cause Claude to suggest invalid properties, wrong import paths, and
removed dependencies when assisting with Spring Boot 4.x projects.