diff --git a/.brazil.json b/.brazil.json
index cb2e43713..5a1d830ab 100644
--- a/.brazil.json
+++ b/.brazil.json
@@ -1,6 +1,6 @@
 {
   "dependencies": {
-    "org.jetbrains.kotlin:kotlin-stdlib:2.0.*": "KotlinStdlib-2.x",
+    "org.jetbrains.kotlin:kotlin-stdlib:2.*": "KotlinStdlib-2.x",
     "org.jetbrains.kotlinx:kotlinx-coroutines-core-jvm:1.*": "KotlinxCoroutinesCoreJvm-1.x",
 
     "com.squareup.okhttp3:okhttp-coroutines:5.*": "OkHttp3Coroutines-5.x",
diff --git a/.changes/1a68d0b7-00e7-45c0-88f6-95e5c39c9c61.json b/.changes/1a68d0b7-00e7-45c0-88f6-95e5c39c9c61.json
new file mode 100644
index 000000000..10ef50220
--- /dev/null
+++ b/.changes/1a68d0b7-00e7-45c0-88f6-95e5c39c9c61.json
@@ -0,0 +1,6 @@
+{
+    "id": "1a68d0b7-00e7-45c0-88f6-95e5c39c9c61",
+    "type": "misc",
+    "description": "⚠️ **IMPORTANT**: Upgrade to Kotlin 2.1.0",
+    "requiresMinorVersionBump": true
+}
\ No newline at end of file
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 0683bfc2e..b90f60288 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,8 +1,8 @@
 [versions]
-kotlin-version = "2.0.21"
+kotlin-version = "2.1.0"
 dokka-version = "1.9.10"
 
-aws-kotlin-repo-tools-version = "0.4.16"
+aws-kotlin-repo-tools-version = "0.4.17"
 
 # libs
 coroutines-version = "1.9.0"
@@ -10,20 +10,20 @@ atomicfu-version = "0.25.0"
 okhttp-version = "5.0.0-alpha.14"
 okhttp4-version = "4.12.0"
 okio-version = "3.9.1"
-otel-version = "1.43.0"
+otel-version = "1.45.0"
 slf4j-version = "2.0.16"
 slf4j-v1x-version = "1.7.36"
 crt-kotlin-version = "0.8.10"
-micrometer-version = "1.13.6"
+micrometer-version = "1.14.2"
+binary-compatibility-validator-version = "0.16.3"
 
 # codegen
 smithy-version = "1.51.0"
-smithy-gradle-version = "0.9.0"
 
 # testing
 junit-version = "5.10.5"
 kotest-version = "5.9.1"
-kotlin-compile-testing-version = "1.6.0"
+kotlin-compile-testing-version = "0.7.0"
 kotlinx-benchmark-version = "0.4.12"
 kotlinx-serialization-version = "1.7.3"
 docker-java-version = "3.4.0"
@@ -80,7 +80,7 @@ smithy-smoke-test-traits = { module = "software.amazon.smithy:smithy-smoke-test-
 junit-jupiter = { module = "org.junit.jupiter:junit-jupiter", version.ref = "junit-version" }
 junit-jupiter-params = { module = "org.junit.jupiter:junit-jupiter-params", version.ref = "junit-version" }
 
-kotlin-compile-testing = {module = "com.github.tschuchortdev:kotlin-compile-testing", version.ref = "kotlin-compile-testing-version" }
+kotlin-compile-testing = {module = "dev.zacsweers.kctfork:core", version.ref = "kotlin-compile-testing-version" }
 kotest-assertions-core = { module = "io.kotest:kotest-assertions-core", version.ref = "kotest-version" }
 kotest-assertions-core-jvm = { module = "io.kotest:kotest-assertions-core-jvm", version.ref = "kotest-version" }
 kotlinx-benchmark-runtime = { module = "org.jetbrains.kotlinx:kotlinx-benchmark-runtime", version.ref = "kotlinx-benchmark-version" }
@@ -104,7 +104,7 @@ dokka = { id = "org.jetbrains.dokka", version.ref = "dokka-version"}
 kotlin-jvm = {id = "org.jetbrains.kotlin.jvm", version.ref = "kotlin-version" }
 kotlin-multiplatform = {id = "org.jetbrains.kotlin.multiplatform", version.ref = "kotlin-version" }
 kotlinx-benchmark = { id = "org.jetbrains.kotlinx.benchmark", version.ref = "kotlinx-benchmark-version" }
-kotlinx-binary-compatibility-validator = { id = "org.jetbrains.kotlinx.binary-compatibility-validator", version = "0.13.2" }
+kotlinx-binary-compatibility-validator = { id = "org.jetbrains.kotlinx.binary-compatibility-validator", version.ref = "binary-compatibility-validator-version" }
 kotlinx-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin-version"}
 aws-kotlin-repo-tools-kmp = { id = "aws.sdk.kotlin.gradle.kmp", version.ref = "aws-kotlin-repo-tools-version" }
 aws-kotlin-repo-tools-smithybuild = { id = "aws.sdk.kotlin.gradle.smithybuild", version.ref = "aws-kotlin-repo-tools-version" }
diff --git a/runtime/auth/aws-signing-tests/jvm/src/aws/smithy/kotlin/runtime/auth/awssigning/tests/SigningSuiteTestBaseJVM.kt b/runtime/auth/aws-signing-tests/jvm/src/aws/smithy/kotlin/runtime/auth/awssigning/tests/SigningSuiteTestBaseJVM.kt
index 904aef564..b3c4202d2 100644
--- a/runtime/auth/aws-signing-tests/jvm/src/aws/smithy/kotlin/runtime/auth/awssigning/tests/SigningSuiteTestBaseJVM.kt
+++ b/runtime/auth/aws-signing-tests/jvm/src/aws/smithy/kotlin/runtime/auth/awssigning/tests/SigningSuiteTestBaseJVM.kt
@@ -28,6 +28,7 @@ import io.ktor.util.*
 import io.ktor.utils.io.*
 import io.ktor.utils.io.core.*
 import kotlinx.coroutines.runBlocking
+import kotlinx.io.readByteArray
 import kotlinx.serialization.json.*
 import org.junit.jupiter.api.Assumptions.assumeTrue
 import org.junit.jupiter.api.Test
@@ -383,7 +384,7 @@ public actual abstract class SigningSuiteTestBase : HasSigner {
         }
 
         if (hasBody) {
-            val bytes = runBlocking { chan.readRemaining().readBytes() }
+            val bytes = runBlocking { chan.readRemaining().readByteArray() }
             builder.body = HttpBody.fromBytes(bytes)
         }
 
diff --git a/tests/compile/src/test/kotlin/software/amazon/smithy/kotlin/codegen/util/TestUtils.kt b/tests/compile/src/test/kotlin/software/amazon/smithy/kotlin/codegen/util/TestUtils.kt
index 02bf209f3..2e64c9d4f 100644
--- a/tests/compile/src/test/kotlin/software/amazon/smithy/kotlin/codegen/util/TestUtils.kt
+++ b/tests/compile/src/test/kotlin/software/amazon/smithy/kotlin/codegen/util/TestUtils.kt
@@ -6,6 +6,7 @@
 
 package software.amazon.smithy.kotlin.codegen.util
 
+import com.tschuchort.compiletesting.JvmCompilationResult
 import com.tschuchort.compiletesting.KotlinCompilation
 import com.tschuchort.compiletesting.SourceFile
 import org.jetbrains.kotlin.compiler.plugin.ExperimentalCompilerApi
@@ -36,8 +37,8 @@ private fun String.slashEscape(char: Char) = this.replace(char.toString(), """\$
  * Captures the result of a model transformation test
  */
 data class ModelChangeTestResult(
-    val originalModelCompilationResult: KotlinCompilation.Result,
-    val updatedModelCompilationResult: KotlinCompilation.Result,
+    val originalModelCompilationResult: JvmCompilationResult,
+    val updatedModelCompilationResult: JvmCompilationResult,
     val compileSuccess: Boolean,
     val compileOutput: String,
 )
@@ -88,7 +89,7 @@ fun compileSdkAndTest(
     testSource: String? = null,
     outputSink: OutputStream = System.out,
     emitSourcesToTmp: Boolean = false,
-): KotlinCompilation.Result {
+): JvmCompilationResult {
     val sdkFileManifest = generateSdk(model)
 
     if (emitSourcesToTmp) {