diff --git a/pom.xml b/pom.xml
index 2e6fb42c2..7aab74c0e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
   <modelVersion>4.0.0</modelVersion>
 
   <artifactId>google-cloud-logging-logback</artifactId>
-  <version>0.129.3-alpha</version><!-- {x-version-update:google-cloud-logging-logback:current} -->
+  <version>0.129.4-alpha-SNAPSHOT</version><!-- {x-version-update:google-cloud-logging-logback:current} -->
   <packaging>jar</packaging>
   <name>Google Cloud Logging Logback Appender</name>
   <url>https://github.com/googleapis/java-logging-logback</url>
diff --git a/samples/snapshot/pom.xml b/samples/snapshot/pom.xml
index 0b0a9b6a4..ad77a19cb 100644
--- a/samples/snapshot/pom.xml
+++ b/samples/snapshot/pom.xml
@@ -28,7 +28,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-logging-logback</artifactId>
-      <version>0.129.3-alpha</version>
+      <version>0.129.4-alpha-SNAPSHOT</version>
     </dependency>
     <!-- {x-version-update-end} -->
 
diff --git a/src/main/java/com/google/cloud/logging/logback/LoggingAppender.java b/src/main/java/com/google/cloud/logging/logback/LoggingAppender.java
index 4501c8f9c..fba8e3e22 100644
--- a/src/main/java/com/google/cloud/logging/logback/LoggingAppender.java
+++ b/src/main/java/com/google/cloud/logging/logback/LoggingAppender.java
@@ -108,7 +108,7 @@ public class LoggingAppender extends UnsynchronizedAppenderBase<ILoggingEvent> {
   // See
   // https://github.com/googleapis/release-please/blob/main/docs/customizing.md#updating-arbitrary-files
   // {x-version-update-start:google-cloud-logging-logback:current}
-  public static final String DEFAULT_INSTRUMENTATION_VERSION = "0.129.3-alpha";
+  public static final String DEFAULT_INSTRUMENTATION_VERSION = "0.129.4-alpha-SNAPSHOT";
   // {x-version-update-end}
   private static boolean instrumentationAdded = false;
   private static Object instrumentationLock = new Object();
diff --git a/versions.txt b/versions.txt
index 65cbc7216..b7ba35f71 100644
--- a/versions.txt
+++ b/versions.txt
@@ -1,4 +1,4 @@
 # Format:
 # module:released-version:current-version
 
-google-cloud-logging-logback:0.129.3-alpha:0.129.3-alpha
+google-cloud-logging-logback:0.129.3-alpha:0.129.4-alpha-SNAPSHOT