diff --git a/CHANGELOG.md b/CHANGELOG.md
index a77cc74e0..89f0e8404 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@
 ### Added
 - Added `showPulse` parameter to `ProgressLayout.progressBar`, allowing you to disable the pulse animation for a bar.
 
+### Changed
+- Update Kotlin to 1.9
+
 ### Fixed
 - Fixed exception thrown in environments that are missing required shared native libraries.
 - Fixed animations clearing too much space when the animation changes size while running. [(#110)](https://github.com/ajalt/mordant/issues/110)
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 4d6e8126d..322e22aa3 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,15 +1,15 @@
 [versions]
-kotlin = "1.8.22"
+kotlin = "1.9.10"
 
 [libraries]
 colormath = "com.github.ajalt.colormath:colormath:3.3.1"
-markdown = "org.jetbrains:markdown:0.4.1"
+markdown = "org.jetbrains:markdown:0.5.0"
 jna-core = "net.java.dev.jna:jna:5.13.0"
 
 # used in tests
-kotest =  "io.kotest:kotest-assertions-core:5.6.2"
+kotest =  "io.kotest:kotest-assertions-core:5.7.2"
 systemrules = "com.github.stefanbirkner:system-rules:1.19.0"
 
 [plugins]
-dokka = "org.jetbrains.dokka:1.8.10"
-publish = "com.vanniktech.maven.publish:0.25.2"
+dokka = "org.jetbrains.dokka:1.9.0"
+publish = "com.vanniktech.maven.publish:0.25.3"
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index c1962a79e..7f93135c4 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 37aef8d3f..ac72c34e8 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.1.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
 networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index aeb74cbb4..0adc8e1a5 100755
--- a/gradlew
+++ b/gradlew
@@ -83,7 +83,8 @@ done
 # This is normally unused
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
@@ -130,10 +131,13 @@ location of your Java installation."
     fi
 else
     JAVACMD=java
-    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
+    fi
 fi
 
 # Increase the maximum file descriptors if we can.
diff --git a/mordant/src/linuxX64Main/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt b/mordant/src/linuxX64Main/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
index 5494966af..83836a0bd 100644
--- a/mordant/src/linuxX64Main/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
+++ b/mordant/src/linuxX64Main/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
@@ -1,5 +1,6 @@
 package com.github.ajalt.mordant.internal
 
+import kotlinx.cinterop.ExperimentalForeignApi
 import kotlinx.cinterop.alloc
 import kotlinx.cinterop.memScoped
 import platform.posix.STDIN_FILENO
@@ -7,10 +8,11 @@ import platform.posix.TIOCGWINSZ
 import platform.posix.ioctl
 import platform.posix.winsize
 
+@OptIn(ExperimentalForeignApi::class)
 internal actual fun getTerminalSize(): Pair<Int, Int>? {
     return memScoped {
         val size = alloc<winsize>()
-        if (ioctl(STDIN_FILENO, TIOCGWINSZ, size) < 0) {
+        if (ioctl(STDIN_FILENO, TIOCGWINSZ.toULong(), size) < 0) {
             null
         } else {
             size.ws_col.toInt() to size.ws_row.toInt()
diff --git a/mordant/src/macosMain/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt b/mordant/src/macosMain/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
index 5494966af..95cc2cac8 100644
--- a/mordant/src/macosMain/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
+++ b/mordant/src/macosMain/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
@@ -1,5 +1,6 @@
 package com.github.ajalt.mordant.internal
 
+import kotlinx.cinterop.ExperimentalForeignApi
 import kotlinx.cinterop.alloc
 import kotlinx.cinterop.memScoped
 import platform.posix.STDIN_FILENO
@@ -7,6 +8,7 @@ import platform.posix.TIOCGWINSZ
 import platform.posix.ioctl
 import platform.posix.winsize
 
+@OptIn(ExperimentalForeignApi::class)
 internal actual fun getTerminalSize(): Pair<Int, Int>? {
     return memScoped {
         val size = alloc<winsize>()
diff --git a/mordant/src/mingwX64Main/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt b/mordant/src/mingwX64Main/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
index 4f7bb9485..f80ceab50 100644
--- a/mordant/src/mingwX64Main/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
+++ b/mordant/src/mingwX64Main/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
@@ -1,3 +1,5 @@
+@file:OptIn(ExperimentalForeignApi::class)
+
 package com.github.ajalt.mordant.internal
 
 import kotlinx.cinterop.*
diff --git a/mordant/src/nativeMain/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt b/mordant/src/nativeMain/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
index 2ca9a6260..a0a373c05 100644
--- a/mordant/src/nativeMain/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
+++ b/mordant/src/nativeMain/kotlin/com/github/ajalt/mordant/internal/MppImpl.kt
@@ -1,13 +1,17 @@
+@file:OptIn(ExperimentalForeignApi::class, ExperimentalNativeApi::class)
+
 package com.github.ajalt.mordant.internal
 
 import com.github.ajalt.mordant.terminal.*
 import kotlinx.cinterop.*
 import platform.posix.*
-import kotlin.native.concurrent.AtomicReference
+import kotlin.concurrent.AtomicInt
+import kotlin.concurrent.AtomicReference
+import kotlin.experimental.ExperimentalNativeApi
 
 
 internal actual class AtomicInt actual constructor(initial: Int) {
-    private val backing = kotlin.native.concurrent.AtomicInt(initial)
+    private val backing = AtomicInt(initial)
     actual fun getAndIncrement(): Int {
         return backing.addAndGet(1) - 1
     }
@@ -64,7 +68,7 @@ internal actual fun makePrintingTerminalCursor(terminal: Terminal): TerminalCurs
 
 // These are for the NativeTerminalCursor, but are top-level since atexit and signal require static
 // functions.
-private val registeredAtExit = kotlin.native.concurrent.AtomicInt(0)
+private val registeredAtExit = AtomicInt(0)
 private const val CURSOR_SHOW_STR = "\u001B[?25h"
 private val CURSOR_SHOW_BUF = CURSOR_SHOW_STR.cstr // .ctr allocates, so we need to do it statically
 
@@ -87,7 +91,7 @@ private fun cursorSigintHandler(signum: Int) {
         STDOUT_FILENO,
         CURSOR_SHOW_BUF,
         // `CURSOR_SHOW_STR.length == 6`. We use a literal since that parameter is a UInt on mingw and a ULong on posix
-        6
+        6u
     )
     signal(SIGINT, existingSigintHandler.value ?: SIG_DFL) // reset signal handling to previous value
     existingSigintHandler.value = null
diff --git a/mordant/src/posixMain/kotlin/com/github/ajalt/mordant/internal/tty.kt b/mordant/src/posixMain/kotlin/com/github/ajalt/mordant/internal/tty.kt
index a1897bd82..7b1133116 100644
--- a/mordant/src/posixMain/kotlin/com/github/ajalt/mordant/internal/tty.kt
+++ b/mordant/src/posixMain/kotlin/com/github/ajalt/mordant/internal/tty.kt
@@ -1,9 +1,8 @@
+@file:OptIn(ExperimentalForeignApi::class)
+
 package com.github.ajalt.mordant.internal
 
-import kotlinx.cinterop.alloc
-import kotlinx.cinterop.convert
-import kotlinx.cinterop.memScoped
-import kotlinx.cinterop.ptr
+import kotlinx.cinterop.*
 import platform.posix.*
 
 // https://www.gnu.org/software/libc/manual/html_node/getpass.html