Spring Boot 4.1.0-RC1 Available Now
Spring Boot 4.1.0-RC1 landed on April 23, 2026, and brings 113 enhancements, documentation improvements, dependency upgrades, and bug fixes. The release candidate stage means the feature set is frozen and this build represents what developers will get in the upcoming GA release.
Three additions stand out for production teams. First, OpenTelemetry SDK environment variable support lets you configure the OTel Java agent and SDK through standard environment variables, aligning Spring Boot's observability wiring with the broader cloud-native ecosystem. Second, HTTP Client SSRF Mitigation via InetAddressFilter adds a structured way to restrict which network destinations your application's HTTP clients can reach—an important security control for apps that make outbound requests based on user input. Third, LazyConnectionDataSourceProxy support gives developers a declarative way to defer database connection acquisition until a transaction actually performs a query, reducing unnecessary connection consumption in read-heavy workloads.
Spring for Apache Pulsar 1.2.17 and 2.0.5 were released on April 22, 2026, and will be bundled into the upcoming Spring Boot 3.5.14, 4.0.6, and 4.1.0-RC1 releases respectively, keeping the Pulsar integration synchronized with the framework's maintenance and feature trains.
The RC1 designation means no further feature additions are planned before GA. Teams targeting Spring Boot 4.1 should validate their applications against RC1 now and report any regressions before the general availability release.
Spring Data 2026.0.0-RC1 Enters Release Candidate Phase
Spring Data 2026.0.0 has reached its first release candidate, published April 17, 2026, paving the way for inclusion in the Spring Boot 4.1.0 GA release. This release candidate polishes several additions that were introduced during the milestone cycle.
Two API additions are notable for Redis users. The new RedisMessageSendingTemplate provides a dedicated, high-level abstraction for publishing messages to Redis pub/sub channels, complementing the existing RedisTemplate with a purpose-built messaging-oriented interface. The ResetStrategy interface targets cache optimizations by giving developers a standardized hook to describe how a cache should be reset between operations, useful in scenarios where cache entries must be cleared in a controlled, conditional manner.
Spring Data 2026.0.0 supersedes the 2025.1 release train and introduces compatibility updates for MongoDB, Redis, JPA, and other backing stores. The RC1 release is aligned with Spring Framework 7.0 and requires Java 21 as its minimum runtime. Spring Boot 4.1.0-RC1 depends on Spring Data 2026.0.0-RC1, so developers previewing Boot 4.1 automatically pick up this Spring Data release.
Teams using Spring Data's Redis support in high-throughput pub/sub scenarios should evaluate the RedisMessageSendingTemplate as a cleaner alternative to manual RedisTemplate channel publishing patterns.
Spring for Apache Pulsar 1.2.17 and 2.0.5 Released
Spring for Apache Pulsar published two maintenance releases on April 22, 2026: version 1.2.17 for applications on the Spring Boot 3.5.x line and version 2.0.5 targeting Spring Boot 4.0.x and the upcoming 4.1.x series. Both releases contain bug fixes and dependency upgrades to keep the integration current with the Pulsar client libraries and the broader Spring ecosystem.
Version 1.2.17 will ship as part of Spring Boot 3.5.14, while version 2.0.5 is bundled into Spring Boot 4.0.6 and is included as a dependency in Spring Boot 4.1.0-RC1. This version alignment means that most developers upgrading to a new Spring Boot maintenance release will automatically receive the corresponding Pulsar integration fix-pack without any explicit version management.
Apache Pulsar continues to gain adoption as an alternative to Kafka for teams that need multi-tenancy, geo-replication, and tiered storage out of the box. Keeping Spring's Pulsar integration on the same release cadence as Boot reduces the friction of maintaining these dependencies in enterprise projects.
Developers working with Spring Pulsar should ensure their Boot version matches the appropriate Pulsar integration version to benefit from these fixes. Release notes for each version are available on the spring-pulsar GitHub repository.
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