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# DataWeave 2.9.0 Release Notes

> For the full documentation index, see: https://docs.mulesoft.com/llms.txt

This MuleSoft programming language simplifies data transformation tasks and serves as Mule runtime’s
expression language for configuring components and connectors. Build powerful integration solutions
with intuitive scripting capabilities.

For more detail, see [DataWeave Language](https://docs.mulesoft.com/dataweave/latest/).

## September 2026

DataWeave 2.9.18 is bundled with the Mule 4.9.21 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>Vulnerable dependencies are upgraded to address reported security vulnerabilities.</p></div></div></td><td><div><div><p>W-23924223</p></div></div></td></tr><tr><td><div><div><p>You can now configure the size of the DataWeave script parser cache by using the <code>mule.weave.script.parser.cache.size</code> system property.</p></div></div></td><td><div><div><p>W-23138851</p></div></div></td></tr><tr><td><div><div><p>A thread-safety livelock no longer occurs in the Java module builder and converter caches.</p></div></div></td><td><div><div><p>W-23652160</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## August 2026

DataWeave 2.9.17 is bundled with the Mule 4.9.20 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>The repeated attribute selector (<code>.*@</code>) now correctly preserves values when processing data structures containing empty map slots.</p></div></div></td><td><div><div><p>W-23457314</p></div></div></td></tr><tr><td><div><div><p>The Jackson library is upgraded to 2.21.5.</p></div></div></td><td><div><div><p>W-23037592</p></div></div></td></tr><tr><td><div><div><p>The <code>per_app_java_bean_cache</code> compatibility flag now correctly reports its creation version as 2.9.</p></div></div></td><td><div><div><p>W-22417507</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## July 2026

DataWeave 2.9.16 is bundled with the Mule 4.9.19 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>Scope resolution errors no longer occur when importing Java classes with self-referential array properties.</p></div></div></td><td><div><div><p>W-22914494</p></div></div></td></tr><tr><td><div><div><p><code>AvroReader</code> no longer causes memory leaks when processing Avro data in long-running flows.</p></div></div></td><td><div><div><p>W-22364385</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## June 2026

DataWeave 2.9.15 is bundled with the Mule 4.9.18 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p><code>StackOverflowError</code> errors no longer occur when computing or converting type metadata for self-referencing recursive types.</p></div></div></td><td><div><div><p>W-21712344</p></div></div></td></tr><tr><td><div><div><p>The Java bean metadata cache no longer performs unnecessary evictions when processing Java POJOs. A new per-app Java bean cache can be enabled with the <code>per_app_java_bean_cache</code> compatibility flag.</p></div></div></td><td><div><div><p>W-22417507</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## May 2026

DataWeave 2.9.14 is bundled with the Mule 4.9.17 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p><code>atBeginningOfDay</code> now returns the midnight offset on DST days, instead of the input offset.</p></div></div></td><td><div><div><p>W-21614817</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## April 2026

DataWeave 2.9.13 is bundled with the Mule 4.9.16 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>The Avro library is upgraded to 1.12.1. The Jackson Core library is upgraded to 2.21.1.</p></div></div></td><td><div><div><p>W-21415439</p></div></div></td></tr><tr><td><div><div><p>The Jakarta Mail library is upgraded to 2.1.5.</p></div></div></td><td><div><div><p>W-21320250</p></div></div></td></tr><tr><td><div><div><p>The range operator now returns null for invalid ranges.</p></div></div></td><td><div><div><p>W-21781423</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## March 2026

DataWeave 2.9.12 is bundled with the Mule 4.9.15 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>The Array range selector operator no longer experiences performance degradation.</p></div></div></td><td><div><div><p>W-20220578</p></div></div></td></tr><tr><td><div><div><p>Concurrent access to <code>KeyValuePairs</code> inside lazy materialized objects no longer causes unexpected behavior.</p></div></div></td><td><div><div><p>W-21045501</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## February 2026

DataWeave 2.9.11 is bundled with the Mule 4.9.13 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>Starting in Mule runtime 4.6, you can now configure materialization settings (<code>mule.dw.enable_vars_materialization_pass</code>).</p></div></div></td><td><div><div><p>W-19580992</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## January 2026

DataWeave 2.9.10 is bundled with the Mule 4.9.12 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>Functions now materialize correctly when the function body contains a single <code>var</code> declaration.</p></div></div></td><td><div><div><p>W-20365331</p></div></div></td></tr><tr><td><div><div><p>The stream reader now processes input with multi-byte characters correctly.</p></div></div></td><td><div><div><p>W-20016549</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## November 2025

DataWeave 2.9.9 is bundled with the Mule 4.9.11 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>The Apache Commons Lang dependency is removed from the distribution.</p></div></div></td><td><div><div><p>W-19803454</p></div></div></td></tr><tr><td><div><div><p>Materialization errors no longer occur when running functions.</p></div></div></td><td><div><div><p>W-19884071</p></div></div></td></tr><tr><td><div><div><p>Single variable materialization now works correctly for <code>unsafe</code> and <code>exists</code> selectors.</p></div></div></td><td><div><div><p>W-19581017</p></div></div></td></tr><tr><td><div><div><p>Each variable is now extracted from <code>vars</code>, allowing its materialization to be managed individually. The <code>mule.dw.enable_vars_materialization_pass</code> compatibility flag is added to preserve the previous materialization behavior.</p></div></div></td><td><div><div><p>W-19580992 / W-17167283</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## October 2025

DataWeave 2.9.8 is bundled with the Mule 4.9.10 release. The Mule patch release addresses these
DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>The <code>take</code> function now works with streaming when argument is larger than the array length.</p></div></div></td><td><div><div><p>W-19168279</p></div></div></td></tr><tr><td><div><div><p><code>java-module</code> now supports object fields access when using different capitalizations.</p></div></div></td><td><div><div><p>W-19477334</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## September 2025

DataWeave 2.9.7 is bundled with the Mule 4.9.9 release. The Mule patch release addresses the
following DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>A memory leak during Weave type schema resolution is now fixed.</p></div></div></td><td><div><div><p>W-19389019</p></div></div></td></tr><tr><td><div><div><p>Potential deadlocks no longer occur when increasing concurrency while parsing DataWeave scripts.</p></div></div></td><td><div><div><p>W-19376546</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## August 2025

DataWeave 2.9.6 is bundled with the Mule 4.9.8 release. The Mule patch release addresses the
following DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>A <code>stackOverflowException</code> error no longer occurs during materialization.</p></div></div></td><td><div><div><p>W-18981240</p></div></div></td></tr><tr><td><div><div><p>The <code>distinctBy</code> function in <code>dw::core::Core</code> now works as expected when used with a CSV input.</p></div></div></td><td><div><div><p>W-18990604</p></div></div></td></tr><tr><td><div><div><p>DataWeave runtime types are now correctly written when outputting Java.</p></div></div></td><td><div><div><p>W-18942349</p></div></div></td></tr><tr><td><div><div><p>Access to multipart content raw value no longer reads the part content.</p></div></div></td><td><div><div><p>W-18892158</p></div></div></td></tr><tr><td><div><div><p>The <code>sizeOf</code> function now works correctly in DataWeave 2.6.14 and later.</p></div></div></td><td><div><div><p>W-18850597</p></div></div></td></tr><tr><td><div><div><p>The <code>orderBy</code> function now evaluates ordering criteria only when required.</p></div></div></td><td><div><div><p>W-18851259</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## July 2025

DataWeave 2.9.5 is bundled with the Mule 4.9.7 release. The Mule patch release addresses the
following DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>This patch update reverts the fix.</p></div></div></td><td><div><div><p>W-17167283</p></div></div></td></tr><tr><td><div><div><p>XML encoding detection now works correctly when the declaration header is missing.</p></div></div></td><td><div><div><p>W-18853667</p></div></div></td></tr><tr><td><div><div><p>The <code>fromCharCode</code> function in <code>dw::core::Strings.</code> now manages surrogate characters correctly.</p></div></div></td><td><div><div><p>W-17204482</p></div></div></td></tr><tr><td><div><div><p>Unicode characters now render correctly at the beginning of the string when using the DataWeave <code>writer</code> function with the <code>onlyData</code> flag enabled.</p></div></div></td><td><div><div><p>W-14855645</p></div></div></td></tr><tr><td><div><div><p>The Apache POI library is now upgraded.</p></div></div></td><td><div><div><p>W-18253747</p></div></div></td></tr><tr><td><div><div><p>Experimental warning messages are no longer logged on DataWeave SDK files.</p></div></div></td><td><div><div><p>W-16384926</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## June 2025

DataWeave 2.9.4 is bundled with the Mule 4.9.6 release. The Mule patch release addresses the
following DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>XML encoding is now detected before selecting a parser.</p></div></div></td><td><div><div><p>W-17637749</p></div></div></td></tr><tr><td><div><div><p>The performance of the <code>orderBy</code> function is now improved.</p></div></div></td><td><div><div><p>W-18439576</p></div></div></td></tr><tr><td><div><div><p>Reading a CSV file inside a MultiPart body now works correctly when performed more than once.</p></div></div></td><td><div><div><p>W-17147598</p></div></div></td></tr><tr><td><div><div><p>A memory leak of the binding context no longer occurs when using the <code>foreach</code> scope.</p></div></div></td><td><div><div><p>W-18472194</p></div></div></td></tr><tr><td><div><div><p><code>CompilationResult</code> no longer retains a reference to the execution frame, which previously caused a memory leak.</p></div></div></td><td><div><div><p>W-18288980</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## May 2025

DataWeave 2.9.3 is bundled with the Mule 4.9.4 release. The Mule patch release addresses the
following DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>Materialization issues no longer occur when using CSV content inside variables.</p></div></div></td><td><div><div><p>W-17167283</p></div></div></td></tr><tr><td><div><div><p>DataWeave now preserves trailing zeroes of single-element sum.</p></div></div></td><td><div><div><p>W-17283050</p></div></div></td></tr><tr><td><div><div><p>A compatibility flag is now added to address the different results produced by calling <code>sizeOf</code> with <code>NumberType</code>.</p></div></div></td><td><div><div><p>W-18020856</p></div></div></td></tr><tr><td><div><div><p>An unnecessary import is now removed from <code>dw::util::Diff</code> to eliminate a warning when running MUnit.</p></div></div></td><td><div><div><p>W-17670504</p></div></div></td></tr><tr><td><div><div><p>DataWeave no longer returns a format error on <code>readUnquotedString</code>.</p></div></div></td><td><div><div><p>W-18118138</p></div></div></td></tr><tr><td><div><div><p>Overflowing no longer occurs while reading large file on multipart format.</p></div></div></td><td><div><div><p>W-17644871</p></div></div></td></tr><tr><td><div><div><p>Performance issues no longer occur when using Message in DataWeave scripts.</p></div></div></td><td><div><div><p>W-18034217</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## April 2025

DataWeave 2.9.2 is bundled with the Mule 4.9.3 release. The Mule patch release addresses the
following DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>Concurrency issues no longer occur when loading modules.</p></div></div></td><td><div><div><p>W-17918619</p></div></div></td></tr><tr><td><div><div><p>The flat file module no longer fails when loading files with a nested depth greater than 50.</p></div></div></td><td><div><div><p>W-17495145</p></div></div></td></tr><tr><td><div><div><p><code>xerces-j</code> is now updated to 2.12.2.</p></div></div></td><td><div><div><p>W-16918194</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## March 2025

DataWeave 2.9.1 is bundled with the Mule 4.9.2 release. The Mule patch release addresses the
following DataWeave issues:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>The Java reflection lookup strategy is now improved for bean instances.</p></div></div></td><td><div><div><p>W-17624594</p></div></div></td></tr><tr><td><div><div><p>Consuming values now work as expected when using overloaded materialized functions.</p></div></div></td><td><div><div><p>W-17588914</p></div></div></td></tr></tbody></table>

For details about the Mule release and patch updates, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

## February 6, 2025

DataWeave 2.9.0 is bundled with the Mule 4.9.0 release. For details about the Mule release, see
[Mule Runtime Engine 4.9.0 Release Notes](https://docs.mulesoft.com/release-notes/mule-runtime/mule-4.9.0-release-notes).

### What’s New

The 2.9.0 version of DataWeave introduces these new features and enhancements:

Extended format support:

- DataWeave introduces support for the Event Stream format. See
  [Event Stream Format](https://docs.mulesoft.com/dataweave/latest/dataweave-formats-eventstream).

General improvements:

- DataWeave incorporates new system properties. See
  [DataWeave System Properties](https://docs.mulesoft.com/dataweave/latest/dataweave-system-properties).

### Compatibility

This table specifies which version of DataWeave is bundled with each Mule runtime engine release:

<table><colgroup><col> <col></colgroup><thead><tr><th>Mule Version</th><th>DataWeave Version</th></tr></thead><tbody><tr><td><p>4.13</p></td><td><p>2.13</p></td></tr><tr><td><p>4.12</p></td><td><p>2.12</p></td></tr><tr><td><p>4.11</p></td><td><p>2.11</p></td></tr><tr><td><p>4.10</p></td><td><p>2.10</p></td></tr><tr><td><p>4.9</p></td><td><p>2.9</p></td></tr><tr><td><p>4.8</p></td><td><p>2.8</p></td></tr><tr><td><p>4.7</p></td><td><p>2.7</p></td></tr><tr><td><p>4.6</p></td><td><p>2.6</p></td></tr><tr><td><p>4.5</p></td><td><p>2.5</p></td></tr><tr><td><p>4.4</p></td><td><p>2.4</p></td></tr><tr><td><p>4.3</p></td><td><p>2.3</p></td></tr><tr><td><p>4.2</p></td><td><p>2.2</p></td></tr><tr><td><p>4.1</p></td><td><p>2.1</p></td></tr><tr><td><p>3.9</p></td><td><p>1.2</p></td></tr><tr><td><p>3.8</p></td><td><p>1.1</p></td></tr><tr><td><p>3.7</p></td><td><p>1.0</p></td></tr></tbody></table>

### Fixed Issues

The release addresses the following DataWeave issues and incorporates all patch updates from the
2.8.0 DataWeave release through January 2025:

<table><colgroup><col> <col></colgroup><thead><tr><th>Issue Resolution</th><th>ID</th></tr></thead><tbody><tr><td><div><div><p>Java module now honors Java bean accessor methods.</p></div></div></td><td><div><div><p>W-17142345</p></div></div></td></tr></tbody></table>

### Upgrade

This version of DataWeave is bundled with Mule. DataWeave upgrades take place through Mule. See
[Mule Upgrades and Patch Updates](https://docs.mulesoft.com/release-notes/mule-runtime/mule-esb#mule-upgrades).

## See Also

- [Salesforce Help](https://help.salesforce.com)

- [MuleSoft Services](https://www.mulesoft.com/support-and-services)

- [Troubleshooting a Failing DataWeave Script](https://docs.mulesoft.com/dataweave/latest/dataweave-troubleshoot)

- [Known Issues](https://help.salesforce.com/s/issues)