diff --git a/.github/workflows/pulsar-ci.yaml b/.github/workflows/pulsar-ci.yaml
index c1912f8e69138..b988595162b9f 100644
--- a/.github/workflows/pulsar-ci.yaml
+++ b/.github/workflows/pulsar-ci.yaml
@@ -258,8 +258,8 @@ jobs:
             group: CLIENT
           - name: Pulsar Metadata
             group: METADATA
-          - name: Protobuf v4
-            group: PROTOBUFV4
+          - name: Protobuf v3
+            group: PROTOBUFV3
 
     steps:
       - name: checkout
diff --git a/distribution/server/src/assemble/LICENSE.bin.txt b/distribution/server/src/assemble/LICENSE.bin.txt
index 876413151d818..daba0f2cfd663 100644
--- a/distribution/server/src/assemble/LICENSE.bin.txt
+++ b/distribution/server/src/assemble/LICENSE.bin.txt
@@ -586,8 +586,8 @@ MIT License
     - com.auth0-jwks-rsa-0.23.1.jar
 Protocol Buffers License
  * Protocol Buffers
-   - com.google.protobuf-protobuf-java-3.25.5.jar -- ../licenses/LICENSE-protobuf.txt
-   - com.google.protobuf-protobuf-java-util-3.25.5.jar -- ../licenses/LICENSE-protobuf.txt
+   - com.google.protobuf-protobuf-java-4.35.0.jar -- ../licenses/LICENSE-protobuf.txt
+   - com.google.protobuf-protobuf-java-util-4.35.0.jar -- ../licenses/LICENSE-protobuf.txt
 
 CDDL-1.1 -- ../licenses/LICENSE-CDDL-1.1.txt
  * Java Servlet API
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 8fdd2dbf477b3..a8a1043ac8389 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -31,7 +31,7 @@ jetty = "12.1.10"
 jersey = "3.1.10"
 jackson = "2.21.3"
 jackson-annotations = "2.21"
-protobuf = "3.25.5"
+protobuf = "4.35.0"
 grpc = "1.75.0"
 slf4j = "2.0.17"
 slog = "0.9.7"
@@ -473,7 +473,7 @@ datasketches-java = { module = "org.apache.datasketches:datasketches-java", vers
 [plugins]
 lightproto = { id = "io.streamnative.lightproto", version.ref = "lightproto" }
 nar = "io.github.merlimat.nar:0.1.3"
-protobuf = "com.google.protobuf:0.9.6"
+protobuf = "com.google.protobuf:0.10.0"
 shadow = { id = "com.gradleup.shadow", version.ref = "shadow" }
 rat = "org.nosphere.apache.rat:0.8.1"
 spotless = "com.diffplug.spotless:8.4.0"
diff --git a/pulsar-build/run_unit_group_gradle.sh b/pulsar-build/run_unit_group_gradle.sh
index 58bc30eaeb2ed..e7bdae740d603 100755
--- a/pulsar-build/run_unit_group_gradle.sh
+++ b/pulsar-build/run_unit_group_gradle.sh
@@ -157,16 +157,16 @@ function test_group_pulsar_io() {
     :pulsar-io:pulsar-io-batch-discovery-triggerers:test
 }
 
-function test_group_protobufv4() {
-  # Rebuild and test with protobuf v4 (overriding the default v3 version)
+function test_group_protobufv3() {
+  # Rebuild and test with protobuf v3 (overriding the default v4 version)
   gradle_test \
-    -PprotobufVersion=4.31.1 \
+    -PprotobufVersion=3.25.5 \
     :pulsar-client-original:test \
     --tests "org.apache.pulsar.client.api.ProtobufSchemaApiSignatureTest" \
     --tests "org.apache.pulsar.client.impl.schema.ProtobufSchemaTest" \
     --tests "org.apache.pulsar.client.impl.schema.ProtobufNativeSchemaTest"
   gradle_test \
-    -PprotobufVersion=4.31.1 \
+    -PprotobufVersion=3.25.5 \
     :pulsar-functions:pulsar-functions-instance:test \
     --tests "org.apache.pulsar.functions.source.TopicSchemaTest" \
     --tests "org.apache.pulsar.functions.instance.JavaInstanceRunnableTest"
diff --git a/pulsar-functions/utils/build.gradle.kts b/pulsar-functions/utils/build.gradle.kts
index c13d03df5f0da..13a8a910f3e55 100644
--- a/pulsar-functions/utils/build.gradle.kts
+++ b/pulsar-functions/utils/build.gradle.kts
@@ -36,6 +36,7 @@ dependencies {
     implementation(libs.protobuf.java.util)
     implementation(libs.byte.buddy)
     implementation(libs.zt.zip)
+    implementation(libs.guava)
 
     testImplementation(libs.wiremock)
     testImplementation(libs.json)