diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 54b9cee0a..8f7501899 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -20,7 +20,7 @@ kotlinPoet = "1.16.0"
 kotlinx-coroutines = "1.6.0"
 kotlinx-serialization = "1.6.3"
 ktlint = "1.2.1"
-protobuf-java = "3.21.7"
+protobuf-java = "4.26.1"
 protobuf-js = "7.2.6"
 protobufGradlePlugin = "0.9.4"
 slf4j = "2.0.6"
diff --git a/testing/conformance/runner/build.gradle.kts b/testing/conformance/runner/build.gradle.kts
index c4c5ccc11..a95e8e0c2 100644
--- a/testing/conformance/runner/build.gradle.kts
+++ b/testing/conformance/runner/build.gradle.kts
@@ -23,7 +23,7 @@ repositories {
     ivy {
         setUrl("https://github.com/ogolberg/")
         patternLayout {
-            artifact("/[organization]/releases/download/v[revision]-0/[artifact]-[classifier]-v[revision]")
+            artifact("/[organization]/releases/download/[revision]/[artifact]-[classifier]-[revision]")
         }
 
         metadataSources {
@@ -57,9 +57,13 @@ object Os {
     }
 }
 
+// protobuf-java version is [java-specific major version].[protobuf version], e.g. 4.26.1
+// the conformance runner version is just [protobuf version], e.g. 26.1
+val conformanceVersion = libs.versions.protobuf.java.get().replace(Regex("^\\d+\\."), "")
+
 dependencies {
     testImplementation(project(":testing:testing-util"))
-    add("conformance", "build-protobuf-conformance-runner:conformance_test_runner:${libs.versions.protobuf.java.get()}") {
+    add("conformance", "build-protobuf-conformance-runner:conformance_test_runner:$conformanceVersion") {
         artifact {
             extension = "exe"
             classifier = Os.CLASSIFIER