Spring Boot 4.1 Adds gRPC Auto-Configuration, SSRF Mitigation, and Kotlin 2.3 Support

2026-06-15 · Source: InfoQ · Field: Technology & Digital — Software Development & Engineering, Cloud Computing & IT Infrastructure, Cybersecurity & Data Privacy · Depth: Intermediate, short

Summary

Broadcom released Spring Boot 4.1 on June 10, 2026, introducing gRPC auto-configuration, HTTP-client SSRF mitigation, and Kotlin 2.3 support. This incremental update, building on Spring Framework 7.0.x, also features lazy datasource connections, automatic async context propagation for "@Async" methods, and enhanced OpenTelemetry support. Notably, jOOQ 3.20 integration requires Java 21. The release marks the first delay in Spring Boot's twice-yearly cadence since May 2020, having been rescheduled twice. Spring Boot 4.1 removes APIs deprecated in version 4.0, such as the "layertools" JAR mode, and deprecates Apache Derby support, Dynatrace V1 API properties, and DevTools LiveReload. It also updates numerous third-party dependencies, including gRPC Java 1.80.0 and OpenTelemetry 1.62, alongside several related Spring project releases.

Key takeaway

For Software Engineers upgrading Spring Boot applications or developing new microservices, Spring Boot 4.1 offers critical enhancements. You should evaluate integrating gRPC auto-configuration for streamlined service communication and implement the new HTTP client SSRF mitigation to bolster application security against internal network attacks. Consider enabling lazy datasource connections to improve startup performance and utilize automatic context propagation for "@Async" methods to simplify observability. Plan for Java 21 if utilizing jOOQ 3.20.

Key insights

Spring Boot 4.1 improves security, performance, and developer experience with gRPC auto-configuration, SSRF mitigation, and lazy connections.

Principles

• Centralized gRPC exception handling improves service reliability.
• Proactive outbound network filtering mitigates SSRF risks.
• Lazy resource initialization reduces application startup times.

Method

Configure InetAddressFilter for outbound request blocking, set "spring.datasource.connection-fetch=lazy" for deferred database connections, and use "@Async" for automatic Micrometer context propagation.

In practice

• Use "@GrpcAdvice" for consistent gRPC exception handling.
• Configure InetAddressFilter to block internal network access.
• Enable "spring.datasource.connection-fetch=lazy" for faster startup.

Topics

• Spring Boot 4.1
• gRPC Auto-configuration
• SSRF Mitigation
• Kotlin 2.3
• OpenTelemetry
• Lazy Connections

Code references

• spring-projects/spring-grpc
• spring-projects/spring-boot
• spring-projects/spring-vault
• spring-projects/spring-integration
• spring-projects/spring-kafka

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Editorial summary, takeaway, and curation by AIssential. Original article published by InfoQ.