diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index caf5ca3f3..8e9be47fc 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.26.0"
+  ".": "0.26.1"
 }
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 228017f96..eb05982d6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 0.26.1 (2025-02-21)
+
+Full Changelog: [v0.26.0...v0.26.1](https://github.com/openai/openai-java/compare/v0.26.0...v0.26.1)
+
+### Documentation
+
+* add immutability explanation to readme ([#243](https://github.com/openai/openai-java/issues/243)) ([5826fb0](https://github.com/openai/openai-java/commit/5826fb0fafa06c647a520f82847319a32ddcbbbb))
+
 ## 0.26.0 (2025-02-20)
 
 Full Changelog: [v0.25.0...v0.26.0](https://github.com/openai/openai-java/compare/v0.25.0...v0.26.0)
diff --git a/README.md b/README.md
index 9dcd39f1c..fd578b983 100644
--- a/README.md
+++ b/README.md
@@ -9,8 +9,8 @@
 
 <!-- x-release-please-start-version -->
 
-[![Maven Central](https://img.shields.io/maven-central/v/com.openai/openai-java)](https://central.sonatype.com/artifact/com.openai/openai-java/0.26.0)
-[![javadoc](https://javadoc.io/badge2/com.openai/openai-java/0.26.0/javadoc.svg)](https://javadoc.io/doc/com.openai/openai-java/0.26.0)
+[![Maven Central](https://img.shields.io/maven-central/v/com.openai/openai-java)](https://central.sonatype.com/artifact/com.openai/openai-java/0.26.1)
+[![javadoc](https://javadoc.io/badge2/com.openai/openai-java/0.26.1/javadoc.svg)](https://javadoc.io/doc/com.openai/openai-java/0.26.1)
 
 <!-- x-release-please-end -->
 
@@ -25,7 +25,7 @@ The REST API documentation can be found on [platform.openai.com](https://platfor
 ### Gradle
 
 ```kotlin
-implementation("com.openai:openai-java:0.26.0")
+implementation("com.openai:openai-java:0.26.1")
 ```
 
 ### Maven
@@ -34,7 +34,7 @@ implementation("com.openai:openai-java:0.26.0")
 <dependency>
     <groupId>com.openai</groupId>
     <artifactId>openai-java</artifactId>
-    <version>0.26.0</version>
+    <version>0.26.1</version>
 </dependency>
 ```
 
@@ -119,6 +119,14 @@ To send a request to the OpenAI API, build an instance of some `Params` class an
 
 For example, `client.chat().completions().create(...)` should be called with an instance of `ChatCompletionCreateParams`, and it will return an instance of `ChatCompletion`.
 
+## Immutability
+
+Each class in the SDK has an associated [builder](https://blogs.oracle.com/javamagazine/post/exploring-joshua-blochs-builder-design-pattern-in-java) or factory method for constructing it.
+
+Each class is [immutable](https://docs.oracle.com/javase/tutorial/essential/concurrency/immutable.html) once constructed. If the class has an associated builder, then it has a `toBuilder()` method, which can be used to convert it back to a builder for making a modified copy.
+
+Because each class is immutable, builder modification will _never_ affect already built class instances.
+
 ## Asynchronous execution
 
 The default client is synchronous. To switch to asynchronous execution, call the `async()` method:
diff --git a/build.gradle.kts b/build.gradle.kts
index 2fd9a5eb0..fb41fce82 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -8,7 +8,7 @@ repositories {
 
 allprojects {
     group = "com.openai"
-    version = "0.26.0" // x-release-please-version
+    version = "0.26.1" // x-release-please-version
 }
 
 subprojects {