diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0a50b231..3f61c37d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,14 +6,11 @@ on:
   pull_request:
 jobs:
   test:
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-latest
     name: Tests
     strategy:
       fail-fast: false
       matrix:
-        # NOTE(olafurpg) Windows is not enabled because it times out due to reasons I don't understand.
-        # os: [windows-latest, ubuntu-latest]
-        os: [ubuntu-latest]
         java: [11, 17, 21]
     steps:
       - uses: actions/checkout@v4
@@ -28,12 +25,8 @@ jobs:
         run: nix develop .#jdk${{ matrix.java }} --command sbt test
 
   docker_test:
-    runs-on: ${{ matrix.os }}
+    runs-on: ubuntu-latest
     name: Docker CLI tests
-    strategy:
-      fail-fast: true
-      matrix:
-        os: [ubuntu-latest]
     steps:
       - uses: actions/checkout@v4
 
diff --git a/build.sbt b/build.sbt
index 419068ee..1349eae0 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,18 +1,14 @@
 import _root_.kotlin.Keys._
-import sbtdocker.DockerfileBase
 import scala.xml.{Node => XmlNode, NodeSeq => XmlNodeSeq, _}
 import scala.xml.transform.{RewriteRule, RuleTransformer}
 import java.io.File
 import java.nio.file.Files
 import java.util.Properties
 import scala.collection.mutable.ListBuffer
-import scala.util.control.NoStackTrace
 
 lazy val V =
   new {
-    val protobuf = "3.15.6"
-    val protoc =
-      "3.17.3" // the oldest protoc version with Apple M1 support, see https://github.com/scalapb/ScalaPB/issues/1024#issuecomment-860126568
+    val protobuf = "4.32.1"
     val coursier = "2.1.9"
     val scalaXml = "2.1.0"
     val moped = "0.2.0"
@@ -25,10 +21,6 @@ lazy val V =
     val minimalMillVersion = "0.10.0"
     val millScipVersion = "0.3.6"
     val kotlinVersion = "2.2.0"
-    // semanticdb-kotlinc has its own (older) protobuf-java codegen pinned to
-    // 3.17.3 to keep the wire format stable for the kotlinc plugin without
-    // perturbing the rest of scip-java.
-    val semanticdbKotlincProtobuf = "3.17.3"
     val kotest = "4.6.3"
     val kctfork = "0.7.1"
   }
@@ -36,15 +28,13 @@ lazy val V =
 inThisBuild(
   List(
     scalaVersion := V.scala213,
-    crossScalaVersions := List(V.scala213),
-    scalafixCaching := true,
     scalacOptions ++= List("-Wunused:imports"),
     semanticdbEnabled := true,
     semanticdbVersion := V.scalameta,
     organization := "com.sourcegraph",
     homepage := Some(url("https://github.com/sourcegraph/scip-java")),
     dynverSeparator := "-",
-    PB.protocVersion := V.protoc,
+    PB.protocVersion := V.protobuf,
     licenses :=
       List("Apache-2.0" -> url("http://www.apache.org/licenses/LICENSE-2.0")),
     developers :=
@@ -112,7 +102,6 @@ lazy val gradlePlugin = project
   .in(file("semanticdb-gradle-plugin"))
   .settings(
     name := "semanticdb-gradle",
-    scalaVersion := V.scala213,
     buildInfoPackage := "com.sourcegraph.scip_java",
     publish / skip := true,
     scalacOptions ++= Seq("-target:11", "-release", "11"),
@@ -393,12 +382,8 @@ lazy val semanticdbKotlinc = project
     Compile / PB.protoSources :=
       Seq((Compile / sourceDirectory).value / "proto"),
     Compile / PB.targets :=
-      Seq(
-        PB.gens.java(V.semanticdbKotlincProtobuf) ->
-          (Compile / sourceManaged).value
-      ),
-    libraryDependencies +=
-      "com.google.protobuf" % "protobuf-java" % V.semanticdbKotlincProtobuf,
+      Seq(PB.gens.java(V.protobuf) -> (Compile / sourceManaged).value),
+    libraryDependencies += "com.google.protobuf" % "protobuf-java" % V.protobuf,
     // kotlin-compiler-embeddable is supplied by kotlinc at runtime
     libraryDependencies +=
       "org.jetbrains.kotlin" % "kotlin-compiler-embeddable" % V.kotlinVersion %
diff --git a/project/plugins.sbt b/project/plugins.sbt
index 74a6360b..f0407f69 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -10,7 +10,6 @@ addSbtPlugin("com.sourcegraph" % "sbt-sourcegraph" % "0.4.4")
 addSbtPlugin("com.lightbend.sbt" % "sbt-java-formatter" % "0.6.1")
 addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.4.3")
 addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.15.0")
-addSbtPlugin("io.spray" % "sbt-revolver" % "0.9.1")
 addSbtPlugin("org.jetbrains.scala" % "sbt-kotlin-plugin" % "3.1.6")
 addSbtPlugin("com.github.sbt.junit" % "sbt-jupiter-interface" % "0.15.1")
 // sbt-jdi-tools appears to fix an error related to this message: