Spring AI 2.1.0-RC1 Update: New Session Conversation Memory and Human Confirmation for Tool Calls

Spring AI 2.1.0-RC1 is released, adding two capabilities: Session conversation memory and Human-in-the-Loop tool call confirmation. The ChatMemory system has been marked deprecated since 2.1.0 and is planned for removal in 3.0.0. Session stores conversations as an append-only event log, with compaction aligned by turn and only boundary events appended; HITL uses the requiresConfirmation flag to pause the tool call loop and resume after waiting for a human decision. The author tested compaction, concurrency, and approval flows on JDK 21 and Spring Boot 4.1.2 using a stub ChatModel, and pointed out that the multi-Agent branch isolation described in the official blog does not exist in 2.1.0-RC1.