# Quarkus 3.39.0

- Product: Quarkus (https://whatsnew.fyi/product/quarkus)
- Vendor: Red Hat
- Date: 2026-08-26
- Version: 3.39.0
- Original notes: https://github.com/quarkusio/quarkus/releases/tag/3.39.0
- Permalink: https://whatsnew.fyi/product/quarkus/releases/3.39.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **removed** — Revert reflection-free Jackson serializers being enabled by default
- **fixed** — Ensure MicrometerRegistryProviderBuildItem has a stable collection order
- **fixed** — Fix @Scheduled method running before @InjectMock is installed in @QuarkusTest
- **added** — Fire StartedExecution CDI event for scheduled jobs
- **changed** — Update to Kotlin 2.4.10
- **changed** — Bump Gradle from 9.6.0 to 9.7.0
- **fixed** — Fix embedding cyclone DX SBOM with minikube extension due to org.jline:jline-parent:4.0.0 dependency
- **changed** — Bump org.bouncycastle:bc-jdk18on-bom from 1.85 to 1.85.2
- **changed** — Bump eu.maveniverse.maven.njord:extension3 from 0.9.9 to 0.9.10
- **changed** — Use testcontainers' oracle-free instead of oracle-xe
- **fixed** — DevUI uses bean class as source for synthetic observers
- **fixed** — Fix jline dependency
- **fixed** — Preserve the configured order of REST compression media types
- **fixed** — Ensure JacksonDeserializerFactory#DeserializationData's constructorFields has a stable order
- **fixed** — Record WebSocket endpoint security checks in a stable order
- **fixed** — Use maps with stable iteration order in OidcGraphQLClientIntegrationProcessor
- **fixed** — Ensure map returned from WebSocketProcessor#collectEndpointSecurityChecks is stable and immutable
- **fixed** — Ensure ctorFields in JacksonDeserializerFactory#deserializeObjectFields is immutable

###### Major changes

  * [#56072](https://github.com/quarkusio/quarkus/pull/56072) - [3.39] Revert "Enable reflection-free Jackson serializers by default"

###### Complete changelog

  * [#55738](https://github.com/quarkusio/quarkus/pull/55738) - Make sure `MicrometerRegistryProviderBuildItem` has a stable collection order
  * [#55756](https://github.com/quarkusio/quarkus/pull/55756) - Datasource guide style review (3.40)
  * [#55834](https://github.com/quarkusio/quarkus/issues/55834) - `@Scheduled` method can run before `@InjectMock` is installed in `@QuarkusTest`
  * [#55891](https://github.com/quarkusio/quarkus/pull/55891) - Scheduler: document halted start mode as a testing workaround
  * [#55902](https://github.com/quarkusio/quarkus/pull/55902) - Bump org.apache.maven.plugins:maven-jar-plugin from 3.5.0 to 3.5.1
  * [#55911](https://github.com/quarkusio/quarkus/issues/55911) - "ScheduledJobStarted" CDI Event for a scheduled job.
  * [#55914](https://github.com/quarkusio/quarkus/pull/55914) - Fire `StartedExecution` CDI event for scheduled jobs
  * [#55947](https://github.com/quarkusio/quarkus/pull/55947) - Update to Kotlin 2.4.10
  * [#55980](https://github.com/quarkusio/quarkus/pull/55980) - Bump Gradle from 9.6.0 to 9.7.0
  * [#55988](https://github.com/quarkusio/quarkus/issues/55988) - Embedding cyclone DX SBOM fails with minikube extension since 3.38.0.CR1 because of org.jline:jline-parent:4.0.0 dependency
  * [#55991](https://github.com/quarkusio/quarkus/issues/55991) - Document implicit transactions for blocking SmallRye GraphQL resolvers when JTA is available
  * [#55995](https://github.com/quarkusio/quarkus/pull/55995) - Bump org.bouncycastle:bc-jdk18on-bom from 1.85 to 1.85.2
  * [#55997](https://github.com/quarkusio/quarkus/pull/55997) - Bump eu.maveniverse.maven.njord:extension3 from 0.9.9 to 0.9.10
  * [#56001](https://github.com/quarkusio/quarkus/pull/56001) - Document implicit transactions for blocking SmallRye GraphQL resolvers
  * [#56002](https://github.com/quarkusio/quarkus/pull/56002) - Use testcontainers' oracle-free instead of oracle-xe
  * [#56008](https://github.com/quarkusio/quarkus/pull/56008) - DevUI: use bean class as source for synthetic observers
  * [#56019](https://github.com/quarkusio/quarkus/pull/56019) - Fix jline dependency
  * [#56020](https://github.com/quarkusio/quarkus/pull/56020) - [3.39] Add quarkus-extension.json
  * [#56041](https://github.com/quarkusio/quarkus/pull/56041) - Preserve the configured order of REST compression media types
  * [#56042](https://github.com/quarkusio/quarkus/pull/56042) - Make sure `JacksonDeserializerFactory#DeserializationData`'s `constructorFields` has a stable order
  * [#56043](https://github.com/quarkusio/quarkus/pull/56043) - Record WebSocket endpoint security checks in a stable order
  * [#56051](https://github.com/quarkusio/quarkus/pull/56051) - Do not use maps with unstable iteration order in `OidcGraphQLClientIntegrationProcessor`
  * [#56052](https://github.com/quarkusio/quarkus/pull/56052) - Make sure map returned from `WebSocketProcessor#collectEndpointSecurityChecks` is stable and immutable
  * [#56053](https://github.com/quarkusio/quarkus/pull/56053) - Make sure `ctorFields` in `JacksonDeserializerFactory#deserializeObjectFields` is immutable
  * [#56054](https://github.com/quarkusio/quarkus/pull/56054) - [3.39] Backport doc categories work to 3.39
  * [#56072](https://github.com/quarkusio/quarkus/pull/56072) - [3.39] Revert "Enable reflection-free Jackson serializers by default"