diff --git a/benchmark-java/build.sbt b/benchmark-java/build.sbt
index 99d891cd..c47d68e8 100644
--- a/benchmark-java/build.sbt
+++ b/benchmark-java/build.sbt
@@ -14,7 +14,7 @@ run / javaOptions ++= List("-Xms1g", "-Xmx1g", "-XX:+PrintGCDetails", "-XX:+Prin
 // generate both client and server (default) in Java
 pekkoGrpcGeneratedLanguages := Seq(PekkoGrpc.Java)
 
-val grpcVersion = "1.65.1" // checked synced by VersionSyncCheckPlugin
+val grpcVersion = "1.66.0" // checked synced by VersionSyncCheckPlugin
 
 val runtimeProject = ProjectRef(file("../"), "runtime")
 
diff --git a/build.sbt b/build.sbt
index 2d9f36a0..a6c8519e 100644
--- a/build.sbt
+++ b/build.sbt
@@ -71,6 +71,10 @@ lazy val codegen = Project(id = "codegen", base = file("codegen"))
     (assembly / mainClass) := Some("org.apache.pekko.grpc.gen.Main"),
     (assembly / assemblyOption) := (assembly / assemblyOption).value.withPrependShellScript(
       Some(sbtassembly.AssemblyPlugin.defaultUniversalScript(shebang = true))),
+    (assembly / assemblyMergeStrategy) := {
+      case PathList("META-INF", _*) => MergeStrategy.discard
+      case _                        => MergeStrategy.deduplicate
+    },
     crossScalaVersions := Dependencies.Versions.CrossScalaForPlugin,
     scalaVersion := scala212,
     Compile / unmanagedSourceDirectories ++= {
diff --git a/gradle-plugin/src/main/groovy/org/apache/pekko/grpc/gradle/PekkoGrpcPluginExtension.groovy b/gradle-plugin/src/main/groovy/org/apache/pekko/grpc/gradle/PekkoGrpcPluginExtension.groovy
index a4b0afff..da3c111c 100644
--- a/gradle-plugin/src/main/groovy/org/apache/pekko/grpc/gradle/PekkoGrpcPluginExtension.groovy
+++ b/gradle-plugin/src/main/groovy/org/apache/pekko/grpc/gradle/PekkoGrpcPluginExtension.groovy
@@ -18,7 +18,7 @@ class PekkoGrpcPluginExtension {
 
     static final String PROTOC_PLUGIN_SCALA_VERSION = "2.12"
 
-    static final String GRPC_VERSION = "1.65.1" // checked synced by VersionSyncCheckPlugin
+    static final String GRPC_VERSION = "1.66.0" // checked synced by VersionSyncCheckPlugin
 
     static final String PLUGIN_CODE = 'org.apache.pekko.grpc.gradle'
 
diff --git a/plugin-tester-java/pom.xml b/plugin-tester-java/pom.xml
index 04d6f04c..3f1e9f98 100644
--- a/plugin-tester-java/pom.xml
+++ b/plugin-tester-java/pom.xml
@@ -25,7 +25,7 @@
     <maven-dependency-plugin.version>3.1.2</maven-dependency-plugin.version>
     <maven-exec-plugin.version>3.0.0</maven-exec-plugin.version>
     <pekko.http.version>1.1.0-M1</pekko.http.version>
-    <grpc.version>1.65.1</grpc.version> <!-- checked synced by VersionSyncCheckPlugin -->
+    <grpc.version>1.66.0</grpc.version> <!-- checked synced by VersionSyncCheckPlugin -->
     <project.encoding>UTF-8</project.encoding>
   </properties>
 
diff --git a/plugin-tester-scala/pom.xml b/plugin-tester-scala/pom.xml
index 71537840..b33ec704 100644
--- a/plugin-tester-scala/pom.xml
+++ b/plugin-tester-scala/pom.xml
@@ -24,7 +24,7 @@
     <maven.compiler.target>1.8</maven.compiler.target>
     <pekko.version>1.1.0-M1</pekko.version>
     <pekko.http.version>1.1.0-M1</pekko.http.version>
-    <grpc.version>1.65.1</grpc.version> <!-- checked synced by VersionSyncCheckPlugin -->
+    <grpc.version>1.66.0</grpc.version> <!-- checked synced by VersionSyncCheckPlugin -->
     <project.encoding>UTF-8</project.encoding>
   </properties>
 
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
index 888cd5d9..85c7eb60 100644
--- a/project/Dependencies.scala
+++ b/project/Dependencies.scala
@@ -32,7 +32,7 @@ object Dependencies {
     val pekkoHttp = PekkoHttpDependency.version
     val pekkoHttpBinary = pekkoHttp.take(3)
 
-    val grpc = "1.65.1" // checked synced by VersionSyncCheckPlugin
+    val grpc = "1.66.0" // checked synced by VersionSyncCheckPlugin
     // Even referenced explicitly in the sbt-plugin's sbt-tests
     // If changing this, remember to update protoc plugin version to align in
     // maven-plugin/src/main/maven/plugin.xml and org.apache.pekko.grpc.sbt.PekkoGrpcPlugin
diff --git a/sbt-plugin/src/sbt-test/gen-scala-server/00-interop/build.sbt b/sbt-plugin/src/sbt-test/gen-scala-server/00-interop/build.sbt
index a6009801..4352e560 100644
--- a/sbt-plugin/src/sbt-test/gen-scala-server/00-interop/build.sbt
+++ b/sbt-plugin/src/sbt-test/gen-scala-server/00-interop/build.sbt
@@ -13,7 +13,7 @@ scalaVersion := "2.12.19"
 
 organization := "org.apache.pekko"
 
-val grpcVersion = "1.65.1" // checked synced by VersionSyncCheckPlugin
+val grpcVersion = "1.66.0" // checked synced by VersionSyncCheckPlugin
 
 libraryDependencies ++= Seq(
   "io.grpc" % "grpc-interop-testing" % grpcVersion % "protobuf-src",
diff --git a/sbt-plugin/src/sbt-test/gen-scala-server/01-gen-basic-server/build.sbt b/sbt-plugin/src/sbt-test/gen-scala-server/01-gen-basic-server/build.sbt
index 77768a2f..2acee0f7 100644
--- a/sbt-plugin/src/sbt-test/gen-scala-server/01-gen-basic-server/build.sbt
+++ b/sbt-plugin/src/sbt-test/gen-scala-server/01-gen-basic-server/build.sbt
@@ -17,8 +17,8 @@ enablePlugins(PekkoGrpcPlugin)
 
 assembly / assemblyMergeStrategy := {
   // https://github.com/akka/akka/issues/29456
-  case PathList("google", "protobuf", _)    => MergeStrategy.discard
-  case PathList("google", "protobuf", _, _) => MergeStrategy.discard
+  case PathList("google", "protobuf", _*) => MergeStrategy.discard
+  case PathList("META-INF", _*)           => MergeStrategy.discard
   case x =>
     val oldStrategy = (assembly / assemblyMergeStrategy).value
     oldStrategy(x)
diff --git a/sbt-plugin/src/sbt-test/gen-scala-server/07-gen-basic-server-with-pekko/build.sbt b/sbt-plugin/src/sbt-test/gen-scala-server/07-gen-basic-server-with-pekko/build.sbt
index fb4c1a37..ff3167d1 100644
--- a/sbt-plugin/src/sbt-test/gen-scala-server/07-gen-basic-server-with-pekko/build.sbt
+++ b/sbt-plugin/src/sbt-test/gen-scala-server/07-gen-basic-server-with-pekko/build.sbt
@@ -15,8 +15,8 @@ enablePlugins(PekkoGrpcPlugin)
 
 assembly / assemblyMergeStrategy := {
   // https://github.com/akka/akka/issues/29456
-  case PathList("google", "protobuf", _)    => MergeStrategy.discard
-  case PathList("google", "protobuf", _, _) => MergeStrategy.discard
+  case PathList("google", "protobuf", _*) => MergeStrategy.discard
+  case PathList("META-INF", _*)           => MergeStrategy.discard
   case x =>
     val oldStrategy = (assembly / assemblyMergeStrategy).value
     oldStrategy(x)