<section name="Release 13.4.0">

<div class="releaseDate">29.03.2026</div>

<p>Breaking backward compatibility:</p>

<ul>

<li>

Improve violation message of ImportOrder.

Author: gianmarco

<a href="https://github.com/checkstyle/checkstyle/issues/8315">#8315</a>

</li>

</ul>

<p>New:</p>

<ul>

<li>

Line break must be present after `{` of non-empty block in switch rule.

Author: Monu Chaudhary

<a href="https://github.com/checkstyle/checkstyle/issues/17565">#17565</a>

</li>

<li>

New Check: IllegalSymbol to forbit emoj in code.

Author: smita_1078

<a href="https://github.com/checkstyle/checkstyle/issues/18065">#18065</a>

</li>

</ul>

<p>Bug fixes:</p>

<ul>

<li>

False-positive: Suppress indentation check when quotes start at the left margin.

Author: Mohit-Sharma

<a href="https://github.com/checkstyle/checkstyle/issues/18228">#18228</a>

</li>

<li>

UnnecessaryNullCheckWithInstanceOf ignores redundant null check for complex cases..

Author: MonuChaudhary14

<a href="https://github.com/checkstyle/checkstyle/issues/17137">#17137</a>

</li>

<li>

False-negative: Member names with underscores.

Author: vivek-0509

<a href="https://github.com/checkstyle/checkstyle/issues/17842">#17842</a>

</li>

</ul>

<p>Notes:</p>

<ul>

<li>

Define violation messages for all violations.

Author: surajgojanur, Zaheer Ahmad, achyuth8055, lithops-zty

<a href="https://github.com/checkstyle/checkstyle/issues/15456">#15456</a>

</li>

<li>

Enforce file size on Java inputs.

Author: lithops-zty, avadhutmali, AsthaDhapodkar, Brijeshthummar02, HamzehAdawi, Carbon14-48

<a href="https://github.com/checkstyle/checkstyle/issues/11163">#11163</a>

</li>

<li>

SarifLoggerTest.java to use verifyWithInlineConfigParserAndLogger.

Author: kairav mittal, Tasneemmhammed0, surajgojanur, avadhutmali, Krish-876, Adam Gamil, Carbon14-48

<a href="https://github.com/checkstyle/checkstyle/issues/16361">#16361</a>

</li>

<li>

Use buildkite CI.

Author: Ayush Singh

<a href="https://github.com/checkstyle/checkstyle/issues/12721">#12721</a>

</li>

<li>

Updating properties in Input files to mention all default properties,.

Author: surajgojanur, Zaheer Ahmad, achyuth8055, Abdo Soliman, developer4949-code, gianmarco, avadhutmali, Eric Tao, HamzehAdawi, Carbon14-48, Newjin

<a href="https://github.com/checkstyle/checkstyle/issues/16807">#16807</a>

</li>

<li>

validation of versions is not working as expected anymore.

Author: ayushactiveat

<a href="https://github.com/checkstyle/checkstyle/issues/12711">#12711</a>

</li>

<li>

Fix xdocs Examples AST Consistency Test (Reduce suppressions list).

Author: Adam Mohamed Gamil, surajgojanur, Zaheer Ahmad

<a href="https://github.com/checkstyle/checkstyle/issues/18435">#18435</a>

</li>

<li>

XpathRegressionXxxxxxXxxxxxTest should have 3 test methods.

Author: Adam Mohamed Gamil, Tasneemmhammed0, Aman Baliyan, achyuth8055, lithops-zty, MiriyalaJayanth-19, daksh, Krish-876, Eric Tao, Carbon14-48, ayushactiveat, surajgojanur, Zaheer Ahmad, Parthib Basu, Akshat Gupta, pirzada-ahmadfaraz

<a href="https://github.com/checkstyle/checkstyle/issues/19064">#19064</a>

</li>

<li>

Enable IDEA inspection JavadocBlankLines inspector.

Author: SteLeo1602

<a href="https://github.com/checkstyle/checkstyle/issues/17298">#17298</a>

</li>

<li>

Update all job that uses 75% or memory to use 90%.

Author: ayushactiveat

<a href="https://github.com/checkstyle/checkstyle/issues/19436">#19436</a>

</li>

<li>

infra: Update Semaphore CI os_image from ubuntu2004 (deprecated, brownout phase).

Author: vivek-0509

<a href="https://github.com/checkstyle/checkstyle/issues/19431">#19431</a>

</li>

<li>

Migrate remaining test files to use getExpectedThrowable instead of fail().

Author: achyuth8055, avadhutmali, pirzada-ahmadfaraz

<a href="https://github.com/checkstyle/checkstyle/issues/19176">#19176</a>

</li>

<li>

Rethink purpose of package section in Check module documentation .

Author: Suryanshu Agrawal

<a href="https://github.com/checkstyle/checkstyle/issues/13194">#13194</a>

</li>

<li>

Add missing property examples to XDocs for Checkstyle Checks.

Author: developer4949-code, avadhutmali, Suryanshu Agrawal

<a href="https://github.com/checkstyle/checkstyle/issues/17449">#17449</a>

</li>

<li>

job no-error-pmd is failing with likely memory problem.

Author: achyuth8055

<a href="https://github.com/checkstyle/checkstyle/issues/19394">#19394</a>

</li>

<li>

doc: fix grammar and capitalization typos in GSOC.md.

Author: Mustafa Enes Kayacı

</li>

<li>

Improve documentation about external DTD loading.

Author: avadhutmali

<a href="https://github.com/checkstyle/checkstyle/issues/10791">#10791</a>

</li>

<li>

Organize openrewrite staticanalysis composite recipes by groups as it is done on

openrewrite website.

Author: Carbon14-48

<a href="https://github.com/checkstyle/checkstyle/issues/18673">#18673</a>

</li>

<li>

Refactor ViolationMessagesMacro::constructMessageKeyUrl to use UrlEncoder.

Author: Krish-876

<a href="https://github.com/checkstyle/checkstyle/issues/13490">#13490</a>

</li>

<li>

POM Property Names.

Author: Carbon14-48

<a href="https://github.com/checkstyle/checkstyle/issues/12508">#12508</a>

</li>

<li>

Fix existing cases of `getFileContents()` usage.

Author: Hariom, gianmarco, Roman Ivanov

<a href="https://github.com/checkstyle/checkstyle/issues/11166">#11166</a>

</li>

<li>

XMLLoggerTest.java to use verifyWithInlineConfigParserAndXmlLogger.

Author: yn-mi12, Adam Gamil

<a href="https://github.com/checkstyle/checkstyle/issues/16360">#16360</a>

</li>

<li>

Trailing comment alignment test fails with tab-based indentation in test input files.

Author: Parthib Basu

<a href="https://github.com/checkstyle/checkstyle/issues/19063">#19063</a>

</li>

<li>

Stable failure of several circleci jobs.

Author: kairav

<a href="https://github.com/checkstyle/checkstyle/issues/19234">#19234</a>

</li>

<li>

Update doc for SuppressWithPlainTextCommentFilter.

Author: ayushactiveat

<a href="https://github.com/checkstyle/checkstyle/issues/11199">#11199</a>

</li>

<li>

create xdoc documetation page to explain details of Xpath support.

Author: ayushactiveat

<a href="https://github.com/checkstyle/checkstyle/issues/9074">#9074</a>

</li>

<li>

Remove Experimental from XPath Filter.

Author: ayushactiveat

<a href="https://github.com/checkstyle/checkstyle/issues/11597">#11597</a>

</li>

<li>

Potential Typo in Running &gt; Command Line &gt; Usage by Classpath Update.

Author: Priyavarshini13

<a href="https://github.com/checkstyle/checkstyle/issues/15292">#15292</a>

</li>

<li>

JavaNCSS : Explain Counting.

Author: Hariom

<a href="https://github.com/checkstyle/checkstyle/issues/15080">#15080</a>

</li>

<li>

MissingNullCaseInSwitch: cases that not obvious how to fix in right way.

Author: Roman Ivanov

<a href="https://github.com/checkstyle/checkstyle/issues/19173">#19173</a>

</li>

<li>

Example of validation for Large Constant Collection.

Author: achyuth8055

<a href="https://github.com/checkstyle/checkstyle/issues/18931">#18931</a>

</li>

<li>

Exclude external and generated files from spell checking.

Author: avadhutmali

<a href="https://github.com/checkstyle/checkstyle/issues/18453">#18453</a>

</li>

<li>

Add instruction to exclude resources files for IntelliJ Idea.

Author: pirzada-ahmadfaraz

<a href="https://github.com/checkstyle/checkstyle/issues/19087">#19087</a>

</li>

<li>

Forbid usage of Truth&#39;s `StandardSubjectBuilder#fail` method..

Author: ayushactiveat

<a href="https://github.com/checkstyle/checkstyle/issues/11315">#11315</a>

</li>

<li>

All contribution and development documentation should live in GitHub.

Author: Suryanshu Agrawal

<a href="https://github.com/checkstyle/checkstyle/issues/14542">#14542</a>

</li>

<li>

test to check indentation trailing comments are vertically aligned.

Author: Carbon14-48

<a href="https://github.com/checkstyle/checkstyle/issues/17128">#17128</a>

</li>

<li>

Re-enable inspections that were temporarily suppressed for Qodana.

Author: ayushactiveat, avadhutmali, pirzada-ahmadfaraz, Youssef Alaa, daksh

<a href="https://github.com/checkstyle/checkstyle/issues/18926">#18926</a>

</li>

<li>

update XdocsExamplesAstConsistencyTest to skip from detecton of diff name of

constructors.

Author: Anushree Bondia

<a href="https://github.com/checkstyle/checkstyle/issues/19000">#19000</a>

</li>

<li>

doc: fix grammar in cmdline (caught, Generates an output suppression XML).

Author: Hasita Pattapu

</li>

<li>

Resolve CheckerFramework violations.

Author: Daniel Gao

<a href="https://github.com/checkstyle/checkstyle/issues/14084">#14084</a>

</li>

<li>

doc: Add 12.x to JRE version table in index.xml.vm.

Author: Paul King

</li>

<li>

Re-enable and Monitor `YAMLSchemaValidation` inspection.

Author: atharv

<a href="https://github.com/checkstyle/checkstyle/issues/14806">#14806</a>

</li>

<li>

Add Check Support for Java 21 Pattern Matching for Switch Syntax: RightCurly.

Author: Parthib Basu

<a href="https://github.com/checkstyle/checkstyle/issues/15033">#15033</a>

</li>

<li>

Metadata/Xdoc generators do not handle {@literal} and incorrectly handle {@code} with

XML special characters.

Author: vivek-0509

<a href="https://github.com/checkstyle/checkstyle/issues/18993">#18993</a>

</li>

<li>

Remove from whitelist file odd words that came from test imput files.

Author: Brijeshthummar02

<a href="https://github.com/checkstyle/checkstyle/issues/5741">#5741</a>

</li>

<li>

update XdocsExamplesAstConsistencyTest to skip modules with no properties.

Author: Brijeshthummar02

<a href="https://github.com/checkstyle/checkstyle/issues/18999">#18999</a>

</li>

<li>

All checks should be used.

Author: vivek-0509

<a href="https://github.com/checkstyle/checkstyle/issues/19045">#19045</a>

</li>

</ul>

</section>