diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index d8b1164..9025ff8 100755
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -15,10 +15,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Set up JDK 17
+      - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
-          java-version: '17'
+          java-version: '21'
           distribution: 'temurin'
           cache: maven
 
diff --git a/README.md b/README.md
index 06c41b8..448ccbf 100755
--- a/README.md
+++ b/README.md
@@ -2,31 +2,62 @@ This is a maintained fork of [Kaned1as/jaudiotagger](https://github.com/Kaned1as
 
 # Jaudiotagger
 
-Jaudiotagger is a Java library for reading and writing audio metadata. It supports a wide range of audio formats, including MP3, Ogg Vorbis, FLAC, WMA, MP4, MPC, Monkey's Audio, OptimFROG, True Audio, WavPack, Musepack, Speex, WAV, AIFF, AU, RealAudio, Opus, and MP2. It also supports ID3v1, ID3v2, Vorbis Comments, APEv2, WMA, MP4, and ASF metadata.
+Jaudiotagger is a Java library for reading and writing audio metadata. It supports a wide range of audio formats,
+including MP3, Ogg Vorbis, FLAC, WMA, MP4, MPC, Monkey's Audio, OptimFROG, True Audio, WavPack, Musepack, Speex, WAV,
+AIFF, AU, RealAudio, Opus, and MP2. It also supports ID3v1, ID3v2, Vorbis Comments, APEv2, WMA, MP4, and ASF metadata.
 
 ## Differences to the original
+
 * Bumped dependency versions
-* Compile target java 17
+* Compile target java 21
 * Removed android compatibility
 * Migrated to junit 5
 * Added: github actions, renovate, semantic releases
 
 ## Motivation
-Mainly I forked the repository because I want to use a maintained version of jaudiotaggger in my [own software](https://github.com/RouHim/disCoverJ).
 
-## Usage
+Mainly I forked the repository because I want to use a maintained version of jaudiotaggger in
+my [own software](https://github.com/RouHim/disCoverJ).
+
+## maven usage
+
 Add this repository to your pom.xml:
+
 ```xml
+
 <repository>
     <id>jitpack.io</id>
     <url>https://jitpack.io</url>
 </repository>
 ```
+
 And then this dependency:
+
 ```xml
+
 <dependency>
     <groupId>com.github.RouHim</groupId>
     <artifactId>jaudiotagger</artifactId>
-    <version>...</version>
+    <version>$version</version>
 </dependency>
 ```
+
+## gradle usage
+
+Add this repository to your build.gradle:
+
+```groovy
+repositories {
+    maven { url 'https://jitpack.io' }
+}
+```
+
+And then this dependency:
+
+```groovy
+dependencies {
+    implementation 'com.github.RouHim:jaudiotagger:$version'
+}
+```
+
+
diff --git a/pom.xml b/pom.xml
index 6ca03e0..f0d16fa 100755
--- a/pom.xml
+++ b/pom.xml
@@ -32,7 +32,7 @@
 
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <java.version>17</java.version>
+        <java.version>21</java.version>
     </properties>
 
     <dependencies>
diff --git a/src/test/java/org/jaudiotagger/tag/mp4/M4aWriteTagTest.java b/src/test/java/org/jaudiotagger/tag/mp4/M4aWriteTagTest.java
index 6252e21..431e953 100755
--- a/src/test/java/org/jaudiotagger/tag/mp4/M4aWriteTagTest.java
+++ b/src/test/java/org/jaudiotagger/tag/mp4/M4aWriteTagTest.java
@@ -22,7 +22,7 @@
 
 public class M4aWriteTagTest {
     private static final int TEST_FILE1_SIZE = 3883555;
-    private static final int TEST_FILE2_SIZE = 3884503;
+    private static final int TEST_FILE2_SIZE = 3884505;
     private static final int TEST_FILE5_SIZE = 119472;
 
     /**