diff --git a/CHANGELOG.md b/CHANGELOG.md
index 62776d9..5f75f5b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.5.1] - 2026-08-15
+
+### Fixed
+
+- Corrected the segment condition documentation on `SegmentConditionGroup` and `SegmentConditionsInput`: conditions **within a group** are joined by `OR`, and **groups** are joined by `AND` — i.e. `(A OR B) AND (C OR D)`. The previous Javadoc stated the inverse. No behaviour change — the API has always evaluated segments this way, and no code paths were touched. Worth a read if you built a segment against the old description, since it may target a wider or narrower audience than you intended.
+
 ## [1.5.0] - 2026-08-14
 
 Covers the reworked bulk contact import (TPL-2105) and the duplicate-create fix. Everything here is additive — code written against 1.4.0 keeps compiling and sends the exact same payloads.
@@ -180,6 +186,7 @@ Initial release.
 - Bearer token auth, Gson-based JSON serialization
 - Structured exceptions: `LettrException`, `LettrApiException`, `LettrValidationException`
 
+[1.5.1]: https://github.com/lettr/lettr-java/compare/v1.5.0...v1.5.1
 [1.5.0]: https://github.com/lettr/lettr-java/compare/v1.4.0...v1.5.0
 [1.4.0]: https://github.com/lettr/lettr-java/compare/v1.3.0...v1.4.0
 [1.1.0]: https://github.com/lettr/lettr-java/compare/v1.0.0...v1.1.0
diff --git a/gradle.properties b/gradle.properties
index 4a16dad..45a4fd1 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,5 +1,5 @@
 GROUP=com.lettr
-VERSION=1.5.0
+VERSION=1.5.1
 POM_ARTIFACT_ID=lettr-java
 POM_NAME=Lettr Java SDK
 POM_DESCRIPTION=Java SDK for the Lettr Email API
diff --git a/src/main/java/com/lettr/services/audience/segments/model/SegmentConditionGroup.java b/src/main/java/com/lettr/services/audience/segments/model/SegmentConditionGroup.java
index f8c3354..2a514c1 100644
--- a/src/main/java/com/lettr/services/audience/segments/model/SegmentConditionGroup.java
+++ b/src/main/java/com/lettr/services/audience/segments/model/SegmentConditionGroup.java
@@ -6,7 +6,7 @@
 import java.util.List;
 
 /**
- * A group of conditions joined by AND. Multiple groups in a segment are joined by OR.
+ * A group of conditions joined by OR. Multiple groups in a segment are joined by AND.
  */
 public class SegmentConditionGroup {
 
diff --git a/src/main/java/com/lettr/services/audience/segments/model/SegmentConditionsInput.java b/src/main/java/com/lettr/services/audience/segments/model/SegmentConditionsInput.java
index 0428c42..e7024f3 100644
--- a/src/main/java/com/lettr/services/audience/segments/model/SegmentConditionsInput.java
+++ b/src/main/java/com/lettr/services/audience/segments/model/SegmentConditionsInput.java
@@ -7,7 +7,7 @@
 
 /**
  * Wrapper used as the {@code conditions} field on segment create/update requests.
- * The top-level groups are joined by OR; conditions within each group are joined by AND.
+ * The top-level groups are joined by AND; conditions within each group are joined by OR.
  */
 public class SegmentConditionsInput {