diff --git a/build.gradle b/build.gradle
index 5d728f20b3..273b425aa6 100644
--- a/build.gradle
+++ b/build.gradle
@@ -89,7 +89,7 @@ allprojects {
 //    apply plugin: 'eclipse'
     apply plugin: 'idea'
 
-    version = '5.5.0'
+    version = '6.0.0-SNAPSHOT'
 }
 
 /**
diff --git a/build.xml b/build.xml
index b7f4b9730c..63b8a4c20e 100644
--- a/build.xml
+++ b/build.xml
@@ -42,7 +42,7 @@ under the License.
 
     <description>The Apache POI project Ant build.</description>
 
-    <property name="version.id" value="5.5.0"/>
+    <property name="version.id" value="6.0.0-SNAPSHOT"/>
     <property name="release.rc" value=""/>
 
     <property environment="env"/>
diff --git a/osgi/pom.xml b/osgi/pom.xml
index da2ed82d60..6a3ed4c277 100644
--- a/osgi/pom.xml
+++ b/osgi/pom.xml
@@ -24,12 +24,12 @@
     <groupId>org.apache.poi</groupId>
     <artifactId>poi-bundle</artifactId>
     <packaging>bundle</packaging>
-    <version>5.5.0</version>
+    <version>6.0.0-SNAPSHOT</version>
 
     <name>Apache POI OSGi bundle</name>
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <poi.version>5.5.0</poi.version>
+        <poi.version>6.0.0-SNAPSHOT</poi.version>
         <pax.exam.version>4.14.0</pax.exam.version>
     </properties>
 
diff --git a/src/documentation/content/xdocs/changes.xml b/src/documentation/content/xdocs/changes.xml
index 2928a57068..aa7419b45d 100644
--- a/src/documentation/content/xdocs/changes.xml
+++ b/src/documentation/content/xdocs/changes.xml
@@ -70,7 +70,7 @@
         </p>
     </section>
 
-    <release version="5.5.0" date="2025-??-??">
+    <release version="5.5.0" date="2025-11-15">
         <summary>
             <summary-item>Upgrade batik dependency to 1.19</summary-item>
             <summary-item>Upgrade bouncycastle dependency to 1.82</summary-item>