diff --git a/clikt/build.gradle.kts b/clikt/build.gradle.kts
index 8c1dbb5b7..0b0fcec3c 100644
--- a/clikt/build.gradle.kts
+++ b/clikt/build.gradle.kts
@@ -1,6 +1,5 @@
 @file:Suppress("UNUSED_VARIABLE", "KotlinRedundantDiagnosticSuppress")
 
-
 plugins {
     kotlin("multiplatform")
     alias(libs.plugins.publish)
@@ -38,43 +37,5 @@ kotlin {
                 api(libs.jimfs)
             }
         }
-
-        val nativeMain by creating {
-            dependsOn(commonMain)
-        }
-        val linuxX64Main by getting {
-            dependsOn(nativeMain)
-        }
-        val mingwX64Main by getting {
-            dependsOn(nativeMain)
-        }
-        val nativeDarwinMain by creating {
-            dependsOn(nativeMain)
-        }
-        val macosX64Main by getting {
-            dependsOn(nativeDarwinMain)
-        }
-        val macosArm64Main by getting {
-            dependsOn(nativeDarwinMain)
-        }
-
-        val nativeTest by creating {
-            dependsOn(commonTest)
-        }
-        val linuxX64Test by getting {
-            dependsOn(nativeTest)
-        }
-        val mingwX64Test by getting {
-            dependsOn(nativeTest)
-        }
-        val nativeDarwinTest by creating {
-            dependsOn(nativeTest)
-        }
-        val macosX64Test by getting {
-            dependsOn(nativeDarwinTest)
-        }
-        val macosArm64Test by getting {
-            dependsOn(nativeDarwinTest)
-        }
     }
 }
diff --git a/clikt/src/commonMain/kotlin/com/github/ajalt/clikt/mpp/MppH.kt b/clikt/src/commonMain/kotlin/com/github/ajalt/clikt/mpp/MppH.kt
index 10e9a1ec2..bf8dd0106 100644
--- a/clikt/src/commonMain/kotlin/com/github/ajalt/clikt/mpp/MppH.kt
+++ b/clikt/src/commonMain/kotlin/com/github/ajalt/clikt/mpp/MppH.kt
@@ -11,6 +11,4 @@ internal expect fun isWindowsMpp(): Boolean
 /** Doesn't return [Nothing], since it's a no-op on the browser */
 internal expect fun exitProcessMpp(status: Int)
 
-internal expect fun isLetterOrDigit(c: Char): Boolean
-
 internal expect fun readFileIfExists(filename: String): String?
diff --git a/clikt/src/commonMain/kotlin/com/github/ajalt/clikt/parameters/options/Option.kt b/clikt/src/commonMain/kotlin/com/github/ajalt/clikt/parameters/options/Option.kt
index 5b5bb5e86..3eec350b8 100644
--- a/clikt/src/commonMain/kotlin/com/github/ajalt/clikt/parameters/options/Option.kt
+++ b/clikt/src/commonMain/kotlin/com/github/ajalt/clikt/parameters/options/Option.kt
@@ -1,8 +1,10 @@
 package com.github.ajalt.clikt.parameters.options
 
 import com.github.ajalt.clikt.completion.CompletionCandidates
-import com.github.ajalt.clikt.core.*
-import com.github.ajalt.clikt.mpp.isLetterOrDigit
+import com.github.ajalt.clikt.core.Context
+import com.github.ajalt.clikt.core.GroupableOption
+import com.github.ajalt.clikt.core.ParameterHolder
+import com.github.ajalt.clikt.core.StaticallyGroupedOption
 import com.github.ajalt.clikt.output.HelpFormatter
 import com.github.ajalt.clikt.parsers.Invocation
 import com.github.ajalt.clikt.sources.ValueSource
@@ -130,7 +132,7 @@ internal fun inferEnvvar(names: Set<String>, envvar: String?, autoEnvvarPrefix:
 /** Split an option token into a pair of prefix to simple name. */
 internal fun splitOptionPrefix(name: String): Pair<String, String> =
     when {
-        name.length < 2 || isLetterOrDigit(name[0]) -> "" to name
+        name.length < 2 || name[0] !in "-@/+" -> "" to name
         name.length > 2 && name[0] == name[1] -> name.slice(0..1) to name.substring(2)
         else -> name.substring(0, 1) to name.substring(1)
     }
diff --git a/clikt/src/jsMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt b/clikt/src/jsMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
index 0b473d824..9f77371df 100644
--- a/clikt/src/jsMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
+++ b/clikt/src/jsMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
@@ -35,12 +35,8 @@ private val impls: JsMppImpls = try {
     BrowserMppImpls
 }
 
-private val LETTER_OR_DIGIT_RE = Regex("""[a-zA-Z0-9]""")
-
 internal actual val String.graphemeLengthMpp: Int get() = replace(ANSI_CODE_RE, "").length
 
-internal actual fun isLetterOrDigit(c: Char): Boolean = LETTER_OR_DIGIT_RE.matches(c.toString())
-
 internal actual fun readEnvvar(key: String): String? = impls.readEnvvar(key)
 internal actual fun isWindowsMpp(): Boolean = impls.isWindowsMpp()
 internal actual fun exitProcessMpp(status: Int): Unit = impls.exitProcessMpp(status)
diff --git a/clikt/src/jvmMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt b/clikt/src/jvmMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
index b8d2c3cbf..442f1f5ea 100644
--- a/clikt/src/jvmMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
+++ b/clikt/src/jvmMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
@@ -18,10 +18,6 @@ internal actual fun exitProcessMpp(status: Int) {
     exitProcess(status)
 }
 
-internal actual fun isLetterOrDigit(c: Char): Boolean {
-    return c.isLetterOrDigit()
-}
-
 internal actual fun readFileIfExists(filename: String): String? {
     val file = File(filename)
     if (!file.isFile) return null
diff --git a/clikt/src/linuxX64Main/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt b/clikt/src/linuxMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
similarity index 100%
rename from clikt/src/linuxX64Main/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
rename to clikt/src/linuxMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
diff --git a/clikt/src/linuxX64Main/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt b/clikt/src/linuxMain/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
similarity index 100%
rename from clikt/src/linuxX64Main/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
rename to clikt/src/linuxMain/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
diff --git a/clikt/src/nativeDarwinMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt b/clikt/src/macosMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
similarity index 100%
rename from clikt/src/nativeDarwinMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
rename to clikt/src/macosMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
diff --git a/clikt/src/nativeDarwinMain/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt b/clikt/src/macosMain/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
similarity index 100%
rename from clikt/src/nativeDarwinMain/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
rename to clikt/src/macosMain/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
diff --git a/clikt/src/mingwX64Main/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt b/clikt/src/mingwMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
similarity index 100%
rename from clikt/src/mingwX64Main/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
rename to clikt/src/mingwMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
diff --git a/clikt/src/mingwX64Main/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt b/clikt/src/mingwMain/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
similarity index 100%
rename from clikt/src/mingwX64Main/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
rename to clikt/src/mingwMain/kotlin/com/github/ajalt/clikt/output/EditorMPP.kt
diff --git a/clikt/src/nativeMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt b/clikt/src/nativeMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
index 07669a766..44de82ef7 100644
--- a/clikt/src/nativeMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
+++ b/clikt/src/nativeMain/kotlin/com/github/ajalt/clikt/mpp/MppImpl.kt
@@ -9,12 +9,8 @@ import platform.posix.fopen
 import kotlin.experimental.ExperimentalNativeApi
 import kotlin.system.exitProcess
 
-private val LETTER_OR_DIGIT_RE = Regex("""[a-zA-Z0-9]""")
-
 internal actual val String.graphemeLengthMpp: Int get() = replace(ANSI_CODE_RE, "").length
 
-internal actual fun isLetterOrDigit(c: Char): Boolean = LETTER_OR_DIGIT_RE.matches(c.toString())
-
 internal actual fun isWindowsMpp(): Boolean = Platform.osFamily == OsFamily.WINDOWS
 
 internal actual fun exitProcessMpp(status: Int): Unit = exitProcess(status)
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 8694255bc..ea763446e 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,5 +1,5 @@
 [versions]
-kotlin = "1.9.10"
+kotlin = "1.9.20"
 
 [libraries]
 mordant = "com.github.ajalt.mordant:mordant:2.2.0"
@@ -14,5 +14,5 @@ kodein = "org.kodein.di:kodein-di-generic-jvm:5.2.0"
 kotlinx-serialization = "org.jetbrains.kotlinx:kotlinx-serialization-json:1.5.1"
 
 [plugins]
-dokka = "org.jetbrains.dokka:1.9.0"
+dokka = "org.jetbrains.dokka:1.9.10"
 publish = "com.vanniktech.maven.publish:0.25.3"