diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index ef2cc9db42..d47020ea5d 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -62,8 +62,7 @@ jobs:
       - name: Test
         shell: bash
         run: |
-          # FIXME K2. Re-enable warnings as errors after this warning is removed: https://youtrack.jetbrains.com/issue/KT-68532
-          # echo "kotlinWarningsAsErrors=true" >> $GITHUB_WORKSPACE/local.properties              
+          echo "kotlinWarningsAsErrors=true" >> $GITHUB_WORKSPACE/local.properties
           ./gradlew apiCheck
           ./gradlew test jvmTest
       - name: Save Test Reports
diff --git a/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/MetricsInterceptor.kt b/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/MetricsInterceptor.kt
index 0ea8ae5e66..8047b870c3 100644
--- a/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/MetricsInterceptor.kt
+++ b/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/MetricsInterceptor.kt
@@ -30,7 +30,7 @@ public object MetricsInterceptor : Interceptor {
         }
 
         val originalResponse = chain.proceed(request)
-        val response = if (originalResponse.body == null || originalResponse.body?.contentLength() == 0L) {
+        val response = if (originalResponse.body.contentLength() == 0L) {
             originalResponse
         } else {
             originalResponse.newBuilder()
diff --git a/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngine.kt b/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngine.kt
index 061c22a13d..a20387d0a0 100644
--- a/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngine.kt
+++ b/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpEngine.kt
@@ -15,6 +15,7 @@ import aws.smithy.kotlin.runtime.net.TlsVersion
 import aws.smithy.kotlin.runtime.operation.ExecutionContext
 import aws.smithy.kotlin.runtime.time.Instant
 import aws.smithy.kotlin.runtime.time.fromEpochMilliseconds
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.job
 import okhttp3.*
 import okhttp3.ConnectionPool
@@ -47,6 +48,7 @@ public class OkHttpEngine(
     private val connectionIdleMonitor = config.connectionIdlePollingInterval?.let { ConnectionIdleMonitor(it) }
     private val client = config.buildClientWithConnectionListener(metrics, connectionIdleMonitor)
 
+    @OptIn(ExperimentalCoroutinesApi::class)
     override suspend fun roundTrip(context: ExecutionContext, request: HttpRequest): HttpCall {
         val callContext = callContext()
 
diff --git a/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpUtils.kt b/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpUtils.kt
index c287228fdf..181ed400c3 100644
--- a/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpUtils.kt
+++ b/runtime/protocol/http-client-engines/http-client-engine-okhttp/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp/OkHttpUtils.kt
@@ -104,7 +104,7 @@ public fun Headers.toOkHttpHeaders(): OkHttpHeaders = OkHttpHeaders.Builder().al
 @InternalApi
 public fun OkHttpResponse.toSdkResponse(): HttpResponse {
     val sdkHeaders = OkHttpHeadersAdapter(headers)
-    val httpBody = if (body == null || body!!.contentLength() == 0L) {
+    val httpBody = if (body.contentLength() == 0L) {
         HttpBody.Empty
     } else {
         object : HttpBody.SourceContent() {
diff --git a/runtime/protocol/http-client-engines/http-client-engine-okhttp4/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp4/OkHttp4Engine.kt b/runtime/protocol/http-client-engines/http-client-engine-okhttp4/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp4/OkHttp4Engine.kt
index ff59823201..026bbd942c 100644
--- a/runtime/protocol/http-client-engines/http-client-engine-okhttp4/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp4/OkHttp4Engine.kt
+++ b/runtime/protocol/http-client-engines/http-client-engine-okhttp4/jvm/src/aws/smithy/kotlin/runtime/http/engine/okhttp4/OkHttp4Engine.kt
@@ -99,7 +99,7 @@ private suspend fun Call.executeAsync(): Response =
                     call: Call,
                     response: Response,
                 ) {
-                    continuation.resume(response) {
+                    continuation.resume(response) { cause, _, _ ->
                         response.closeQuietly()
                     }
                 }
diff --git a/runtime/runtime-core/common/src/aws/smithy/kotlin/runtime/util/JMESPath.kt b/runtime/runtime-core/common/src/aws/smithy/kotlin/runtime/util/JMESPath.kt
index 9b691a79a2..c8437b2b33 100644
--- a/runtime/runtime-core/common/src/aws/smithy/kotlin/runtime/util/JMESPath.kt
+++ b/runtime/runtime-core/common/src/aws/smithy/kotlin/runtime/util/JMESPath.kt
@@ -62,8 +62,7 @@ public fun Any?.type(): String = when (this) {
     is List<*>, is Array<*> -> "array"
     is Number -> "number"
     is Any -> "object"
-    null -> "null"
-    else -> throw Exception("Undetected type for: $this")
+    else -> "null"
 }
 
 // Collection `flattenIfPossible` functions