diff --git a/build.gradle.kts b/build.gradle.kts
index 223a12d33465..fb692ee58f41 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -115,9 +115,7 @@ subprojects {
 
   tasks.withType<KotlinCompile> {
     kotlinOptions {
-      apiVersion = "1.4"
       jvmTarget = JavaVersion.VERSION_1_8.toString()
-
       freeCompilerArgs = listOf(
         "-Xjvm-default=all",
         "-opt-in=kotlin.RequiresOptIn"
diff --git a/mockwebserver/src/main/kotlin/mockwebserver3/MockWebServer.kt b/mockwebserver/src/main/kotlin/mockwebserver3/MockWebServer.kt
index 937c4c0f0697..4f5a65ad60a5 100644
--- a/mockwebserver/src/main/kotlin/mockwebserver3/MockWebServer.kt
+++ b/mockwebserver/src/main/kotlin/mockwebserver3/MockWebServer.kt
@@ -75,7 +75,6 @@ import okhttp3.internal.http2.Header
 import okhttp3.internal.http2.Http2Connection
 import okhttp3.internal.http2.Http2Stream
 import okhttp3.internal.immutableListOf
-import okhttp3.internal.lowercase
 import okhttp3.internal.platform.Platform
 import okhttp3.internal.threadFactory
 import okhttp3.internal.toImmutableList
diff --git a/okhttp-coroutines/src/jvmTest/kotlin/okhttp3/SuspendCallTest.kt b/okhttp-coroutines/src/jvmTest/kotlin/okhttp3/SuspendCallTest.kt
index 230d1ea47cd1..999984588ce1 100644
--- a/okhttp-coroutines/src/jvmTest/kotlin/okhttp3/SuspendCallTest.kt
+++ b/okhttp-coroutines/src/jvmTest/kotlin/okhttp3/SuspendCallTest.kt
@@ -15,7 +15,7 @@
  *
  */
 
-@file:OptIn(ExperimentalCoroutinesApi::class, ExperimentalTime::class)
+@file:OptIn(ExperimentalCoroutinesApi::class)
 
 package okhttp3
 
@@ -39,7 +39,6 @@ import org.junit.jupiter.api.fail
 import java.io.IOException
 import java.util.concurrent.TimeUnit
 import kotlin.time.Duration.Companion.seconds
-import kotlin.time.ExperimentalTime
 
 @ExtendWith(MockWebServerExtension::class)
 class SuspendCallTest(
diff --git a/okhttp-sse/src/main/kotlin/okhttp3/sse/internal/ServerSentEventReader.kt b/okhttp-sse/src/main/kotlin/okhttp3/sse/internal/ServerSentEventReader.kt
index 1e3f9f36274d..53d60aea0617 100644
--- a/okhttp-sse/src/main/kotlin/okhttp3/sse/internal/ServerSentEventReader.kt
+++ b/okhttp-sse/src/main/kotlin/okhttp3/sse/internal/ServerSentEventReader.kt
@@ -16,7 +16,6 @@
 package okhttp3.sse.internal
 
 import java.io.IOException
-import okhttp3.internal.code
 import okhttp3.internal.toLongOrDefault
 import okio.Buffer
 import okio.BufferedSource
diff --git a/okhttp-tls/src/main/kotlin/okhttp3/tls/internal/der/DerReader.kt b/okhttp-tls/src/main/kotlin/okhttp3/tls/internal/der/DerReader.kt
index eb63fdb27b42..b51a19dca44a 100644
--- a/okhttp-tls/src/main/kotlin/okhttp3/tls/internal/der/DerReader.kt
+++ b/okhttp-tls/src/main/kotlin/okhttp3/tls/internal/der/DerReader.kt
@@ -17,7 +17,6 @@ package okhttp3.tls.internal.der
 
 import java.math.BigInteger
 import java.net.ProtocolException
-import okhttp3.internal.code
 import okio.Buffer
 import okio.BufferedSource
 import okio.ByteString
diff --git a/okhttp-tls/src/main/kotlin/okhttp3/tls/internal/der/DerWriter.kt b/okhttp-tls/src/main/kotlin/okhttp3/tls/internal/der/DerWriter.kt
index 62b959612d46..7db879bfa535 100644
--- a/okhttp-tls/src/main/kotlin/okhttp3/tls/internal/der/DerWriter.kt
+++ b/okhttp-tls/src/main/kotlin/okhttp3/tls/internal/der/DerWriter.kt
@@ -16,7 +16,6 @@
 package okhttp3.tls.internal.der
 
 import java.math.BigInteger
-import okhttp3.internal.code
 import okio.Buffer
 import okio.BufferedSink
 import okio.ByteString
diff --git a/okhttp/src/commonMain/kotlin/okhttp3/CacheControl.kt b/okhttp/src/commonMain/kotlin/okhttp3/CacheControl.kt
index 434c8658d17e..b6b7fc6e4307 100644
--- a/okhttp/src/commonMain/kotlin/okhttp3/CacheControl.kt
+++ b/okhttp/src/commonMain/kotlin/okhttp3/CacheControl.kt
@@ -13,13 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-@file:OptIn(ExperimentalTime::class)
-
 package okhttp3
 
 import kotlin.time.DurationUnit
-import kotlin.time.ExperimentalTime
 
 /**
  * A Cache-Control header with cache directives from a server or client. These directives set policy
diff --git a/okhttp/src/commonMain/kotlin/okhttp3/internal/-CacheControlCommon.kt b/okhttp/src/commonMain/kotlin/okhttp3/internal/-CacheControlCommon.kt
index 312a00b0cfa2..8871efa3a24a 100644
--- a/okhttp/src/commonMain/kotlin/okhttp3/internal/-CacheControlCommon.kt
+++ b/okhttp/src/commonMain/kotlin/okhttp3/internal/-CacheControlCommon.kt
@@ -13,13 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-@file:OptIn(ExperimentalTime::class)
-
 package okhttp3.internal
 
+import kotlin.time.Duration
 import kotlin.time.DurationUnit
-import kotlin.time.ExperimentalTime
 import kotlin.time.toDuration
 import okhttp3.CacheControl
 import okhttp3.Headers
diff --git a/okhttp/src/commonMain/kotlin/okhttp3/internal/-UtilCommon.kt b/okhttp/src/commonMain/kotlin/okhttp3/internal/-UtilCommon.kt
index aab0547e6b93..0a3bf35888d1 100644
--- a/okhttp/src/commonMain/kotlin/okhttp3/internal/-UtilCommon.kt
+++ b/okhttp/src/commonMain/kotlin/okhttp3/internal/-UtilCommon.kt
@@ -394,17 +394,3 @@ internal fun <T> interleave(a: Iterable<T>, b: Iterable<T>): List<T> {
     }
   }
 }
-
-@Suppress("DEPRECATION")
-inline val Char.code
-  get() = this.toInt()
-
-expect inline fun String.lowercase(): String
-
-expect inline fun String.uppercase(): String
-
-inline fun <E> buildList(builderAction: MutableList<E>.() -> Unit): List<E> {
-  return mutableListOf<E>().apply {
-    builderAction()
-  }
-}
diff --git a/okhttp/src/commonTest/kotlin/okhttp3/CacheControlTest.kt b/okhttp/src/commonTest/kotlin/okhttp3/CacheControlTest.kt
index d4b9143b8ba2..162f5b9acbdc 100644
--- a/okhttp/src/commonTest/kotlin/okhttp3/CacheControlTest.kt
+++ b/okhttp/src/commonTest/kotlin/okhttp3/CacheControlTest.kt
@@ -13,9 +13,6 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-@file:OptIn(ExperimentalTime::class)
-
 package okhttp3
 
 import assertk.assertThat
@@ -24,7 +21,6 @@ import assertk.assertions.isFalse
 import assertk.assertions.isTrue
 import kotlin.test.Test
 import kotlin.time.DurationUnit
-import kotlin.time.ExperimentalTime
 
 class CacheControlTest {
   @Test
diff --git a/okhttp/src/commonTest/kotlin/okhttp3/MediaTypeTest.kt b/okhttp/src/commonTest/kotlin/okhttp3/MediaTypeTest.kt
index 9931205c7729..77e20e04b9e7 100644
--- a/okhttp/src/commonTest/kotlin/okhttp3/MediaTypeTest.kt
+++ b/okhttp/src/commonTest/kotlin/okhttp3/MediaTypeTest.kt
@@ -20,7 +20,6 @@ import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNull
 import okhttp3.MediaType.Companion.toMediaTypeOrNull
-import okhttp3.internal.uppercase
 
 /**
  * Test MediaType API and parsing.
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/Cache.kt b/okhttp/src/jvmMain/kotlin/okhttp3/Cache.kt
index 7bf0f2cb10cd..78bc29aa3708 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/Cache.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/Cache.kt
@@ -31,7 +31,6 @@ import okhttp3.internal.cache.CacheRequest
 import okhttp3.internal.cache.CacheStrategy
 import okhttp3.internal.cache.DiskLruCache
 import okhttp3.internal.closeQuietly
-import okhttp3.internal.code
 import okhttp3.internal.concurrent.TaskRunner
 import okhttp3.internal.http.HttpMethod
 import okhttp3.internal.http.StatusLine
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/CacheControl.kt b/okhttp/src/jvmMain/kotlin/okhttp3/CacheControl.kt
index be6394ef4de8..bbd45b5e5011 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/CacheControl.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/CacheControl.kt
@@ -13,18 +13,18 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-@file:OptIn(ExperimentalTime::class)
-
 package okhttp3
 
 import java.util.concurrent.TimeUnit
 import kotlin.time.DurationUnit
-import kotlin.time.ExperimentalTime
 import okhttp3.internal.commonBuild
 import okhttp3.internal.commonClampToInt
 import okhttp3.internal.commonForceCache
 import okhttp3.internal.commonForceNetwork
 import okhttp3.internal.commonImmutable
+import okhttp3.internal.commonMaxAge
+import okhttp3.internal.commonMaxStale
+import okhttp3.internal.commonMinFresh
 import okhttp3.internal.commonNoCache
 import okhttp3.internal.commonNoStore
 import okhttp3.internal.commonNoTransform
@@ -150,18 +150,11 @@ actual class CacheControl internal actual constructor(
 
     actual fun immutable() = commonImmutable()
 
-    // We are compiling with kotlin 1.6 but need to run with older versions at runtime. For
-    // maximum compat we therefore need to handle both the case where DurationUnit is typealiased
-    // to TimeUnit (as it was pre-1.6) and where it is a distinct wrapper enum (in 1.6). We also
-    // can't use durationUnit.toTimeUnit() because that doesn't exist in the typealiased case.
-    // This function should work in either case.
-    internal fun toJavaTimeUnit(durationUnit: DurationUnit) = TimeUnit.valueOf(durationUnit.name)
-
-    actual fun maxAge(maxAge: Int, timeUnit: DurationUnit) = maxAge(maxAge, toJavaTimeUnit(timeUnit))
+    actual fun maxAge(maxAge: Int, timeUnit: DurationUnit) = commonMaxAge(maxAge, timeUnit)
 
-    actual fun maxStale(maxStale: Int, timeUnit: DurationUnit) = maxStale(maxStale, toJavaTimeUnit(timeUnit))
+    actual fun maxStale(maxStale: Int, timeUnit: DurationUnit) = commonMaxStale(maxStale, timeUnit)
 
-    actual fun minFresh(minFresh: Int, timeUnit: DurationUnit) = minFresh(minFresh, toJavaTimeUnit(timeUnit))
+    actual fun minFresh(minFresh: Int, timeUnit: DurationUnit) = commonMinFresh(minFresh, timeUnit)
 
     /**
      * Sets the maximum age of a cached response. If the cache response's age exceeds [maxAge], it
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/Challenge.kt b/okhttp/src/jvmMain/kotlin/okhttp3/Challenge.kt
index 73e736810e1e..d2d9593afb5e 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/Challenge.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/Challenge.kt
@@ -23,7 +23,6 @@ import kotlin.text.Charsets.ISO_8859_1
 import okhttp3.internal.commonEquals
 import okhttp3.internal.commonHashCode
 import okhttp3.internal.commonToString
-import okhttp3.internal.lowercase
 
 actual class Challenge actual constructor(
   @get:JvmName("scheme") actual val scheme: String,
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/Cookie.kt b/okhttp/src/jvmMain/kotlin/okhttp3/Cookie.kt
index 60dd327239fc..fbe8b5c8f4d9 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/Cookie.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/Cookie.kt
@@ -23,12 +23,10 @@ import java.util.Locale
 import java.util.regex.Pattern
 import okhttp3.internal.UTC
 import okhttp3.internal.canParseAsIpAddress
-import okhttp3.internal.code
 import okhttp3.internal.delimiterOffset
 import okhttp3.internal.http.MAX_DATE
 import okhttp3.internal.http.toHttpDateString
 import okhttp3.internal.indexOfControlOrNonAscii
-import okhttp3.internal.lowercase
 import okhttp3.internal.publicsuffix.PublicSuffixDatabase
 import okhttp3.internal.toCanonicalHost
 import okhttp3.internal.trimSubstring
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/FormBody.kt b/okhttp/src/jvmMain/kotlin/okhttp3/FormBody.kt
index 107c22c4b818..747086a8d028 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/FormBody.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/FormBody.kt
@@ -21,7 +21,6 @@ import okhttp3.HttpUrl.Companion.FORM_ENCODE_SET
 import okhttp3.HttpUrl.Companion.canonicalize
 import okhttp3.HttpUrl.Companion.percentDecode
 import okhttp3.MediaType.Companion.toMediaType
-import okhttp3.internal.code
 import okhttp3.internal.toImmutableList
 import okio.Buffer
 import okio.BufferedSink
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/Headers.kt b/okhttp/src/jvmMain/kotlin/okhttp3/Headers.kt
index 295cfaede55e..9f7358d77441 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/Headers.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/Headers.kt
@@ -46,7 +46,6 @@ import okhttp3.internal.headersCheckName
 import okhttp3.internal.http.toHttpDateOrNull
 import okhttp3.internal.http.toHttpDateString
 import okhttp3.internal.http2.Header
-import okhttp3.internal.lowercase
 import org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement
 
 @Suppress("NAME_SHADOWING")
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/HttpUrl.kt b/okhttp/src/jvmMain/kotlin/okhttp3/HttpUrl.kt
index 5f851e6371d2..2b8723e82b8c 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/HttpUrl.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/HttpUrl.kt
@@ -26,7 +26,6 @@ import kotlin.text.Charsets.UTF_8
 import okhttp3.HttpUrl.Companion.toHttpUrl
 import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
 import okhttp3.internal.canParseAsIpAddress
-import okhttp3.internal.code
 import okhttp3.internal.delimiterOffset
 import okhttp3.internal.indexOfFirstNonAsciiWhitespace
 import okhttp3.internal.indexOfLastNonAsciiWhitespace
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/MultipartBody.kt b/okhttp/src/jvmMain/kotlin/okhttp3/MultipartBody.kt
index e3db54693b66..cf6dbedb0492 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/MultipartBody.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/MultipartBody.kt
@@ -18,7 +18,6 @@ package okhttp3
 import java.io.IOException
 import java.util.UUID
 import okhttp3.MediaType.Companion.toMediaType
-import okhttp3.internal.code
 import okhttp3.internal.toImmutableList
 import okio.Buffer
 import okio.BufferedSink
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/internal/-UtilJvm.kt b/okhttp/src/jvmMain/kotlin/okhttp3/internal/-UtilJvm.kt
index 89e356e1cba4..5362de662dff 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/internal/-UtilJvm.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/internal/-UtilJvm.kt
@@ -313,10 +313,3 @@ internal inline fun Any.assertThreadDoesntHoldLock() {
     throw AssertionError("Thread ${Thread.currentThread().name} MUST NOT hold lock on $this")
   }
 }
-actual inline fun String.lowercase() = this.toLowerCase(Locale.ROOT)
-
-actual inline fun String.uppercase() = this.toUpperCase(Locale.ROOT)
-
-fun String.lowercase(locale: Locale) = this.toLowerCase(locale)
-
-fun String.uppercase(locale: Locale) = this.toUpperCase(locale)
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/internal/cache/DiskLruCache.kt b/okhttp/src/jvmMain/kotlin/okhttp3/internal/cache/DiskLruCache.kt
index 605768a797d1..c227de098ad2 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/internal/cache/DiskLruCache.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/internal/cache/DiskLruCache.kt
@@ -22,7 +22,6 @@ import java.io.IOException
 import okhttp3.internal.assertThreadHoldsLock
 import okhttp3.internal.cache.DiskLruCache.Editor
 import okhttp3.internal.closeQuietly
-import okhttp3.internal.code
 import okhttp3.internal.concurrent.Task
 import okhttp3.internal.concurrent.TaskRunner
 import okhttp3.internal.deleteContents
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/internal/http/HttpHeaders.kt b/okhttp/src/jvmMain/kotlin/okhttp3/internal/http/HttpHeaders.kt
index 71ba05870d90..f149430c60bd 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/internal/http/HttpHeaders.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/internal/http/HttpHeaders.kt
@@ -27,7 +27,6 @@ import okhttp3.CookieJar
 import okhttp3.Headers
 import okhttp3.HttpUrl
 import okhttp3.Response
-import okhttp3.internal.code
 import okhttp3.internal.headersContentLength
 import okhttp3.internal.platform.Platform
 import okhttp3.internal.skipAll
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/internal/http2/Hpack.kt b/okhttp/src/jvmMain/kotlin/okhttp3/internal/http2/Hpack.kt
index 9b219eaa87fe..6ec4e3ea53a1 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/internal/http2/Hpack.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/internal/http2/Hpack.kt
@@ -20,7 +20,6 @@ import java.util.Arrays
 import java.util.Collections
 import java.util.LinkedHashMap
 import okhttp3.internal.and
-import okhttp3.internal.code
 import okhttp3.internal.http2.Header.Companion.RESPONSE_STATUS
 import okhttp3.internal.http2.Header.Companion.TARGET_AUTHORITY
 import okhttp3.internal.http2.Header.Companion.TARGET_METHOD
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/internal/http2/Http2ExchangeCodec.kt b/okhttp/src/jvmMain/kotlin/okhttp3/internal/http2/Http2ExchangeCodec.kt
index 64e2791dd830..baf5ff0c11f7 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/internal/http2/Http2ExchangeCodec.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/internal/http2/Http2ExchangeCodec.kt
@@ -42,7 +42,6 @@ import okhttp3.internal.http2.Header.Companion.TARGET_PATH_UTF8
 import okhttp3.internal.http2.Header.Companion.TARGET_SCHEME
 import okhttp3.internal.http2.Header.Companion.TARGET_SCHEME_UTF8
 import okhttp3.internal.immutableListOf
-import okhttp3.internal.lowercase
 import okio.Sink
 import okio.Source
 
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/internal/publicsuffix/PublicSuffixDatabase.kt b/okhttp/src/jvmMain/kotlin/okhttp3/internal/publicsuffix/PublicSuffixDatabase.kt
index 60b02fb8956e..0ed111fe4713 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/internal/publicsuffix/PublicSuffixDatabase.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/internal/publicsuffix/PublicSuffixDatabase.kt
@@ -21,7 +21,6 @@ import java.net.IDN
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.atomic.AtomicBoolean
 import okhttp3.internal.and
-import okhttp3.internal.code
 import okhttp3.internal.platform.Platform
 import okio.GzipSource
 import okio.buffer
diff --git a/okhttp/src/jvmMain/kotlin/okhttp3/internal/tls/OkHostnameVerifier.kt b/okhttp/src/jvmMain/kotlin/okhttp3/internal/tls/OkHostnameVerifier.kt
index 6ef6e876a017..a43791bb2813 100644
--- a/okhttp/src/jvmMain/kotlin/okhttp3/internal/tls/OkHostnameVerifier.kt
+++ b/okhttp/src/jvmMain/kotlin/okhttp3/internal/tls/OkHostnameVerifier.kt
@@ -25,7 +25,6 @@ import java.util.Locale
 import javax.net.ssl.HostnameVerifier
 import javax.net.ssl.SSLException
 import javax.net.ssl.SSLSession
-import okhttp3.internal.lowercase
 
 /**
  * A HostnameVerifier consistent with [RFC 2818][rfc_2818].
diff --git a/okhttp/src/jvmTest/java/okhttp3/CallTest.kt b/okhttp/src/jvmTest/java/okhttp3/CallTest.kt
index 5e038e82f6dc..959dfed0cd6c 100644
--- a/okhttp/src/jvmTest/java/okhttp3/CallTest.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/CallTest.kt
@@ -67,7 +67,6 @@ import okhttp3.internal.DoubleInetAddressDns
 import okhttp3.internal.RecordingOkAuthenticator
 import okhttp3.internal.addHeaderLenient
 import okhttp3.internal.closeQuietly
-import okhttp3.internal.code
 import okhttp3.internal.http.RecordingProxySelector
 import okhttp3.internal.userAgent
 import okhttp3.okio.LoggingFilesystem
diff --git a/okhttp/src/jvmTest/java/okhttp3/ResponseBodyJvmTest.kt b/okhttp/src/jvmTest/java/okhttp3/ResponseBodyJvmTest.kt
index 285bbc42b1d6..f1e6187fd80e 100644
--- a/okhttp/src/jvmTest/java/okhttp3/ResponseBodyJvmTest.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/ResponseBodyJvmTest.kt
@@ -32,7 +32,6 @@ import java.lang.StringBuilder
 import java.nio.charset.StandardCharsets
 import java.util.concurrent.atomic.AtomicBoolean
 import okhttp3.internal.and
-import okhttp3.internal.code
 import okio.ByteString.Companion.decodeHex
 import org.assertj.core.api.Assertions.assertThat
 
diff --git a/okhttp/src/jvmTest/java/okhttp3/URLConnectionTest.kt b/okhttp/src/jvmTest/java/okhttp3/URLConnectionTest.kt
index 4441588c95ce..e4561802ca24 100644
--- a/okhttp/src/jvmTest/java/okhttp3/URLConnectionTest.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/URLConnectionTest.kt
@@ -63,10 +63,8 @@ import okhttp3.TestUtil.assertSuppressed
 import okhttp3.internal.RecordingAuthenticator
 import okhttp3.internal.RecordingOkAuthenticator
 import okhttp3.internal.addHeaderLenient
-import okhttp3.internal.code
 import okhttp3.internal.http.HTTP_PERM_REDIRECT
 import okhttp3.internal.http.HTTP_TEMP_REDIRECT
-import okhttp3.internal.lowercase
 import okhttp3.internal.platform.Platform.Companion.get
 import okhttp3.internal.userAgent
 import okhttp3.testing.Flaky
diff --git a/okhttp/src/jvmTest/java/okhttp3/UrlComponentEncodingTester.kt b/okhttp/src/jvmTest/java/okhttp3/UrlComponentEncodingTester.kt
index d9a7126632eb..c82691793cd7 100644
--- a/okhttp/src/jvmTest/java/okhttp3/UrlComponentEncodingTester.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/UrlComponentEncodingTester.kt
@@ -17,9 +17,7 @@ package okhttp3
 
 import okhttp3.HttpUrl.Companion.toHttpUrl
 import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
-import okhttp3.internal.code
 import okhttp3.internal.format
-import okhttp3.internal.lowercase
 import okio.Buffer
 import okio.ByteString.Companion.encodeUtf8
 import org.junit.jupiter.api.Assertions.fail
diff --git a/okhttp/src/jvmTest/java/okhttp3/WebPlatformUrlTestData.kt b/okhttp/src/jvmTest/java/okhttp3/WebPlatformUrlTestData.kt
index da5a0aa77d62..458d3f91d516 100644
--- a/okhttp/src/jvmTest/java/okhttp3/WebPlatformUrlTestData.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/WebPlatformUrlTestData.kt
@@ -15,7 +15,6 @@
  */
 package okhttp3
 
-import okhttp3.internal.code
 import okhttp3.internal.format
 import okio.Buffer
 import okio.BufferedSource
diff --git a/okhttp/src/jvmTest/java/okhttp3/internal/cache/DiskLruCacheTest.kt b/okhttp/src/jvmTest/java/okhttp3/internal/cache/DiskLruCacheTest.kt
index 4e151af95806..a96d741f79f3 100644
--- a/okhttp/src/jvmTest/java/okhttp3/internal/cache/DiskLruCacheTest.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/internal/cache/DiskLruCacheTest.kt
@@ -41,7 +41,6 @@ import java.io.FileNotFoundException
 import java.io.IOException
 import java.util.ArrayDeque
 import java.util.NoSuchElementException
-import okhttp3.internal.code
 
 class FileSystemParamProvider: SimpleProvider() {
   override fun arguments() = listOf(
diff --git a/okhttp/src/jvmTest/java/okhttp3/internal/http2/Http2ConnectionTest.kt b/okhttp/src/jvmTest/java/okhttp3/internal/http2/Http2ConnectionTest.kt
index a4f26f974ada..8e9b22364cb4 100644
--- a/okhttp/src/jvmTest/java/okhttp3/internal/http2/Http2ConnectionTest.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/internal/http2/Http2ConnectionTest.kt
@@ -26,7 +26,6 @@ import okhttp3.TestUtil.headerEntries
 import okhttp3.TestUtil.repeat
 import okhttp3.internal.EMPTY_BYTE_ARRAY
 import okhttp3.internal.EMPTY_HEADERS
-import okhttp3.internal.code
 import okhttp3.internal.concurrent.TaskFaker
 import okhttp3.internal.concurrent.TaskRunner
 import okhttp3.internal.notifyAll
diff --git a/okhttp/src/jvmTest/java/okhttp3/internal/http2/HttpOverHttp2Test.kt b/okhttp/src/jvmTest/java/okhttp3/internal/http2/HttpOverHttp2Test.kt
index 8b70f8a5ca95..77ea66306717 100644
--- a/okhttp/src/jvmTest/java/okhttp3/internal/http2/HttpOverHttp2Test.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/internal/http2/HttpOverHttp2Test.kt
@@ -65,7 +65,6 @@ import okhttp3.TestUtil.repeat
 import okhttp3.internal.DoubleInetAddressDns
 import okhttp3.internal.EMPTY_REQUEST
 import okhttp3.internal.RecordingOkAuthenticator
-import okhttp3.internal.code
 import okhttp3.internal.connection.RealConnection
 import okhttp3.internal.discard
 import okhttp3.testing.Flaky
diff --git a/okhttp/src/jvmTest/java/okhttp3/internal/idn/Punycode.kt b/okhttp/src/jvmTest/java/okhttp3/internal/idn/Punycode.kt
index c64b618ab230..5d8718828060 100644
--- a/okhttp/src/jvmTest/java/okhttp3/internal/idn/Punycode.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/internal/idn/Punycode.kt
@@ -15,7 +15,6 @@
  */
 package okhttp3.internal.idn
 
-import okhttp3.internal.code
 import okio.Buffer
 
 /**
diff --git a/okhttp/src/jvmTest/java/okhttp3/internal/idn/StringprepTablesReaderTest.kt b/okhttp/src/jvmTest/java/okhttp3/internal/idn/StringprepTablesReaderTest.kt
index 41a912cf1dbf..460787216e3e 100644
--- a/okhttp/src/jvmTest/java/okhttp3/internal/idn/StringprepTablesReaderTest.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/internal/idn/StringprepTablesReaderTest.kt
@@ -17,7 +17,6 @@ package okhttp3.internal.idn
 
 import kotlin.test.Test
 import kotlin.test.assertEquals
-import okhttp3.internal.code
 import okio.Buffer
 import okio.FileSystem
 import okio.Path.Companion.toPath
diff --git a/okhttp/src/jvmTest/java/okhttp3/internal/idn/stringprepTablesReader.kt b/okhttp/src/jvmTest/java/okhttp3/internal/idn/stringprepTablesReader.kt
index b22aebb10620..17a092c3b1a2 100644
--- a/okhttp/src/jvmTest/java/okhttp3/internal/idn/stringprepTablesReader.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/internal/idn/stringprepTablesReader.kt
@@ -15,7 +15,6 @@
  */
 package okhttp3.internal.idn
 
-import okhttp3.internal.code
 import okio.Buffer
 import okio.BufferedSource
 import okio.ByteString.Companion.encodeUtf8
diff --git a/okhttp/src/jvmTest/java/okhttp3/internal/ws/WebSocketWriterTest.kt b/okhttp/src/jvmTest/java/okhttp3/internal/ws/WebSocketWriterTest.kt
index 94562f0d5dcc..6b9a9b34be08 100644
--- a/okhttp/src/jvmTest/java/okhttp3/internal/ws/WebSocketWriterTest.kt
+++ b/okhttp/src/jvmTest/java/okhttp3/internal/ws/WebSocketWriterTest.kt
@@ -17,7 +17,6 @@ package okhttp3.internal.ws
 
 import java.util.Random
 import okhttp3.TestUtil.repeat
-import okhttp3.internal.code
 import okhttp3.internal.format
 import okhttp3.internal.ws.WebSocketProtocol.OPCODE_BINARY
 import okhttp3.internal.ws.WebSocketProtocol.OPCODE_TEXT
diff --git a/okhttp/src/nonJvmMain/kotlin/okhttp3/internal/-UtilNonJvm.kt b/okhttp/src/nonJvmMain/kotlin/okhttp3/internal/-UtilNonJvm.kt
index 72de79033563..282d4edcf096 100644
--- a/okhttp/src/nonJvmMain/kotlin/okhttp3/internal/-UtilNonJvm.kt
+++ b/okhttp/src/nonJvmMain/kotlin/okhttp3/internal/-UtilNonJvm.kt
@@ -16,11 +16,4 @@
 
 package okhttp3.internal
 
-import kotlin.text.lowercase as kotlinLowerCase
-import kotlin.text.uppercase as kotlinUpperCase
-
 actual typealias HttpUrlRepresentation = String
-
-actual inline fun String.lowercase() = this.kotlinLowerCase()
-
-actual inline fun String.uppercase() = this.kotlinUpperCase()