diff --git a/docs/pages/release_notes.md b/docs/pages/release_notes.md
index a6b5973f9e..37b11bdee8 100644
--- a/docs/pages/release_notes.md
+++ b/docs/pages/release_notes.md
@@ -31,12 +31,19 @@ the suppressions with a `NOPMD` comment. See [Suppressing warnings](pmd_userdocs
     to cyclomatic complexity, this rule uses "Cognitive Complexity", which is a measure of how
     difficult it is for humans to read and understand a method.
 
+*   The Rule {% rule "apex/errorprone/TestMethodsMustBeInTestClasses" %} (`apex-errorprone`) finds test methods
+    that are not residing in a test class. The test methods should be moved to a proper test class.
+    Support for tests inside functional classes was removed in Spring-13 (API Version 27.0), making classes
+    that violate this rule fail compile-time. This rule is however useful when dealing with legacy code.
+
 ### Fixed Issues
 
 *   apex
     *   [#1087](https://github.com/pmd/pmd/issues/1087): \[apex] Support suppression via //NOPMD
 *   apex-design
     *   [#2162](https://github.com/pmd/pmd/issues/2162): \[apex] Cognitive Complexity rule
+*   apex-errorprone
+    *   [#639](https://github.com/pmd/pmd/issues/639): \[apex] Test methods should not be in classes other than test classes
 *   doc
     *   [#2274](https://github.com/pmd/pmd/issues/2274): \[doc] Java API documentation for PMD
 *   java
@@ -135,6 +142,7 @@ methods on {% jdoc apex::lang.apex.ast.ApexParserVisitor %} and its implementati
 *   [#2278](https://github.com/pmd/pmd/pull/2278): \[java] fix UnusedImports rule for ambiguous static on-demand imports - [Kris Scheibe](https://github.com/kris-scheibe)
 *   [#2279](https://github.com/pmd/pmd/pull/2279): \[apex] Add support for suppressing violations using the // NOPMD comment - [Gwilym Kuiper](https://github.com/gwilymatgearset)
 *   [#2297](https://github.com/pmd/pmd/pull/2297): \[apex] Cognitive complexity metrics - [Gwilym Kuiper](https://github.com/gwilymatgearset)
+*   [#2317](https://github.com/pmd/pmd/pull/2317): \[apex] New Rule - Test Methods Must Be In Test Classes - [Brian Nørremark](https://github.com/noerremark)
 
 {% endtocmaker %}
 
diff --git a/pmd-core/src/main/resources/rulesets/releases/6220.xml b/pmd-core/src/main/resources/rulesets/releases/6220.xml
index e810572d8e..13b0cbc5b7 100644
--- a/pmd-core/src/main/resources/rulesets/releases/6220.xml
+++ b/pmd-core/src/main/resources/rulesets/releases/6220.xml
@@ -9,5 +9,6 @@ This ruleset contains links to rules that are new in PMD v6.22.0
   </description>
 
     <rule ref="category/apex/design.xml/CognitiveComplexity"/>
+    <rule ref="category/apex/errorprone.xml/TestMethodsMustBeInTestClasses"/>
 
 </ruleset>