Jackson Release 2.21

Jackson Version 2.21 is being developed, as of September 2025.

This wiki page gives a list of links to all changes (with brief descriptions) that will eventually be included, as well as about original plans for bigger changes (and in some cases changes to plans, postponing).

Status

Version is under development (under branch 2.x)

Patches

No release yet.

Documentation

Articles, Blog posts

New Modules

Changes, compatibility

Android

Same as Jackson 2.20, SDK 26

JDK

Same as Jackson 2.20; mostly Java 8, with some modules requiring later JDKs:

• jackson-datatype-hibernate: JDK 11 for some modules
• jackson-jakarta-providers: JDK 11

Kotlin

Same as Jackson 2.20?

Compatibility: datatype modules

Changes, behavior

None

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Major focus area(s)

Most wanted Features implemented

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Full Change list

Changes, core

Annotations

• #314: Add JsonInclude.Value convenience constants
• #316: Make JsonFormat.Features java.io.Serializable

Streaming

• #1470: Add method copyCurrentStructureExact() to JsonGenerator
• #1477: Add JsonGenerator.has(StreamWriteCapability) convenience method

Databind

• #1547: Un-deprecate SerializationFeature.WRITE_EMPTY_JSON_ARRAYS
• #5045: If there is a no-parameter constructor marked as JsonCreator and a constructor reported as DefaultCreator, latter is incorrectly used
• #5293: Fix minor typo in PropertyBindingException.getMessageSuffix()
• #5313: Expose getConverter() in StdDelegatingSerializer for improved customizability

Changes, datatypes

Eclipse Collections

• #198: Add support for MutableSortedMap/ImmutableSortedMap deserialization

Changes, other

Jackson-jr

• #208: Support reading of double[]