diff --git a/.github/workflows/compatibility.yml b/.github/workflows/compatibility.yml
new file mode 100644
index 00000000..eb1ab81b
--- /dev/null
+++ b/.github/workflows/compatibility.yml
@@ -0,0 +1,29 @@
+name: Gradle and Java compatibility
+
+on:
+  push:
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  compatibility:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        java: ['11', '14', '15', '24']
+    name: Java ${{ matrix.java }} / Gradle 8.14.6
+    steps:
+      - uses: actions/checkout@v7
+        with:
+          submodules: recursive
+      - uses: actions/setup-java@v6
+        with:
+          distribution: zulu
+          java-version: ${{ matrix.java }}
+      - uses: gradle/actions/setup-gradle@v6
+      - run: ./gradlew build compileSamplesKotlin dokka --console=plain
+      - run: ./template/gradlew -p template --include-build "$PWD" tasks --all --console=plain
diff --git a/.gitignore b/.gitignore
index 573dff46..890510e0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,3 +11,6 @@ misc/
 
 # Ignore Gradle build output directory
 build
+
+# Kotlin compiler cache
+.kotlin
diff --git a/README.md b/README.md
index 36af9d05..92d1e816 100644
--- a/README.md
+++ b/README.md
@@ -217,14 +217,15 @@ ftppass=password
 
 To use SubKt you will need:
 
-* A [recent version of the JDK](https://www.oracle.com/uk/java/technologies/javase-downloads.html)
+* A [JDK](https://www.oracle.com/java/technologies/downloads/), Java 11–24 (tested on Java 11, 14, 15, and 24). The included wrapper downloads Gradle 8.14.6 automatically.
 * [mkvmerge](https://mkvtoolnix.download/downloads.html)
 
 Ensure that both `java` and `mkvmerge` are available on the PATH.
-Instructions for setting the PATH for JDK 14 on Windows can be found [here](https://docs.oracle.com/en/java/javase/14/install/installation-jdk-microsoft-windows-platforms.html#GUID-96EB3876-8C7A-4A25-9F3A-A2983FEC016A).
+Set `JAVA_HOME` to your JDK installation and add its `bin` directory to the PATH.
 The same procedure can be used to add `mkvmerge` to the PATH; take note of where you installed/extracted it.
 
-Download the [project template](https://github.com/Myaamori/SubKt/releases/download/0.1.19/subkt-template-0.1.19.zip) and place the files in the directory where you keep your project files.
+Use the files in the [`template`](template) directory for new projects. Older release archives contain an obsolete Gradle wrapper and do not include this JDK upgrade.
+Until this upgrade is released, use a local SubKt checkout as described below, passing `--include-build /absolute/path/to/SubKt` when running the template's wrapper.
 After you have modified `build.gradle.kts` and `sub.properties` as needed, you can run tasks using `gradlew`.
 For instance, to run the `mux` task for episode `03`, navigate to the same directory as the `build.gradle.kts` file in a terminal, and run `./gradlew mux.03`.
 On Windows, simply run `gradlew mux.03` from `cmd.exe`.
@@ -232,15 +233,23 @@ On Windows, simply run `gradlew mux.03` from `cmd.exe`.
 **Note**: The first time you run `gradlew` may take some time as Gradle as well as all dependencies need to be downloaded.
 Future runs will be much quicker.
 
+## Working alongside older projects
+
+The updated SubKt source and template use Gradle 8.14.6 on Java 11–24. Collaborators can run the same project's `gradlew` with different supported Java installations, without editing the wrapper configuration or installing another JDK. The wrapper downloads Gradle and verifies its SHA-256 checksum.
+
+Keep older projects on their existing SubKt and wrapper versions. For an updated project, copy both launchers and the `gradle/wrapper` directory from the template and select the updated SubKt source. Until this upgrade is released, use `--include-build` as described below; the template's default `subktVersion=0.1.19` still selects the old release. Gradle 8.14.6 cannot run on Java 25 or newer.
+
 ## Building and using a local checkout
 
 Initialize the bundled torrent library, then build with the installed JDK:
 
 ```sh
 git submodule update --init --recursive
-./gradlew build
+./gradlew build compileSamplesKotlin
 ```
 
+Build plugins come from the Gradle Plugin Portal and dependencies from Maven Central; JCenter is no longer used. Java and Kotlin compile to Java 11 bytecode without downloading a separate JDK. Kotlin dependencies match the host Gradle's embedded Kotlin runtime, and Kotlin language/API version 2.0 keeps the plugin readable by Gradle 8.14's Kotlin DSL compiler.
+
 To use this checkout from the included template:
 
 ```sh
@@ -251,8 +260,17 @@ cd template
 
 For a template copied elsewhere, pass `--include-build /absolute/path/to/SubKt`. Gradle substitutes the local checkout for the `myaa:subkt` dependency, including uncommitted changes. Keep `subktRepo` and `subktVersion` configured: without `--include-build`, they select the Git repository and version as usual.
 
+Run `./gradlew dokka` to generate Markdown API documentation in `build/dokka/gfm`. The checked-in documentation is not overwritten.
+
 Projects using FTPS with `sslSessionReuse` enabled also need the two `--add-opens` JVM arguments in the template's `gradle.properties`. They allow the existing session-reuse implementation to access the JDK's SSL session cache on Java 17+. Merge these arguments into any existing `org.gradle.jvmargs` setting.
 
+The compatibility workflow builds the plugin and samples, runs the functional tests, generates documentation, and loads the template on Java 11, 14, 15, and 24. Select a supported JDK with `JAVA_HOME`, then run:
+
+```sh
+./gradlew build compileSamplesKotlin dokka
+./template/gradlew -p template --include-build "$PWD" tasks --all
+```
+
 # Manual
 
 A detailed description of the different tasks, functions and classes provided can be found in [the documentation](docs/subkt/index.md).
diff --git a/build.gradle.kts b/build.gradle.kts
index bc6093ee..169f8533 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,11 +1,12 @@
 import java.net.URI
-import java.net.URL
-import org.jetbrains.dokka.gradle.DokkaTask
+import org.jetbrains.dokka.gradle.formats.DokkaFormatPlugin
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
 
 plugins {
-    kotlin("jvm") version "1.3.72"
+    kotlin("jvm") version "2.4.21"
     `java-gradle-plugin`
-    id("org.jetbrains.dokka") version "0.9.18"
+    id("org.jetbrains.dokka") version "2.2.0"
 }
 
 gradlePlugin {
@@ -40,8 +41,9 @@ sourceSets {
 }
 
 dependencies {
-    implementation(kotlin("stdlib-jdk8", "1.3.72"))
-    implementation(kotlin("reflect", "1.3.72"))
+    // Use the host Gradle's Kotlin runtime, including 2.0.21 on Gradle 8.14.
+    implementation(kotlin("stdlib", embeddedKotlinVersion))
+    implementation(kotlin("reflect", embeddedKotlinVersion))
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.7")
     implementation(gradleApi())
     implementation(gradleKotlinDsl())
@@ -61,46 +63,66 @@ dependencies {
     implementation("commons-codec:commons-codec:1.14")
 
     "samplesImplementation"(sourceSets["main"].output)
+    testImplementation(gradleTestKit())
+    testImplementation(kotlin("test-junit", embeddedKotlinVersion))
 }
 
-tasks {
-    withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach {
-        kotlinOptions.jvmTarget = "1.8"
-        kotlinOptions.freeCompilerArgs += "-Xopt-in=kotlin.RequiresOptIn"
+// Keep the plugin usable on Java 11–16 with Gradle 8.14 as well as modern Gradle.
+java {
+    sourceCompatibility = JavaVersion.VERSION_11
+    targetCompatibility = JavaVersion.VERSION_11
+}
+
+kotlin {
+    compilerOptions {
+        jvmTarget.set(JvmTarget.JVM_11)
+        // Gradle 8.14's Kotlin DSL compiler must be able to read our metadata.
+        languageVersion.set(KotlinVersion.KOTLIN_2_0)
+        apiVersion.set(KotlinVersion.KOTLIN_2_0)
     }
+}
 
-    val dokka by getting(DokkaTask::class) {
-        outputFormat = "gfm"
-        outputDirectory = "docs"
+tasks.withType<JavaCompile>().configureEach {
+    options.release.set(11)
+}
 
-        // configuration {
-        noStdlibLink = false
-        noJdkLink = false
-        jdkVersion = 9
-        //platform = "JVM"
+// Dokka v2 ships HTML/Javadoc formats; retain the existing Markdown output too.
+abstract class DokkaGfmPlugin : DokkaFormatPlugin("gfm")
+apply<DokkaGfmPlugin>()
 
-        includes = listOf("src/docs/markdown/packages.md")
-        samples = listOf("src/samples/kotlin/tasks.kt")
+dependencies {
+    add("dokkaGfmPlugin", "org.jetbrains.dokka:gfm-plugin:2.2.0")
+}
 
-        externalDocumentationLink {
-            url = URL("https://docs.gradle.org/current/javadoc/")
+dokka {
+    dokkaPublications.named("gfm") {
+        outputDirectory.set(layout.buildDirectory.dir("dokka/gfm"))
+    }
+    dokkaSourceSets.named("main") {
+        jdkVersion.set(11)
+        includes.from("src/docs/markdown/packages.md")
+        samples.from("src/samples/kotlin/tasks.kt")
+        externalDocumentationLinks.register("gradle") {
+            url.set(URI("https://docs.gradle.org/current/javadoc/"))
+            packageListUrl.set(URI("https://docs.gradle.org/current/javadoc/element-list"))
         }
-
-        externalDocumentationLink {
-            url = URL("https://velocity.apache.org/engine/2.2/apidocs/")
+        externalDocumentationLinks.register("velocity") {
+            url.set(URI("https://velocity.apache.org/engine/2.2/apidocs/"))
         }
-
-        packageOptions/*perPackageOption*/ {
-            prefix = "com.turn.ttorrent"
-            suppress = true
+        perPackageOption {
+            matchingRegex.set("com\\.turn\\.ttorrent.*")
+            suppress.set(true)
         }
-
-        linkMapping {
-            // replace \ with / since only unix paths are allowed
-            dir = project.file("src/main/kotlin").absolutePath.replace('\\', '/')
-            url = "https://github.com/Myaamori/SubKt/blob/$version/src/main/kotlin"
-            suffix = "#L"
+        sourceLink {
+            localDirectory.set(file("src/main/kotlin"))
+            remoteUrl.set(URI("https://github.com/Myaamori/SubKt/blob/$version/src/main/kotlin"))
+            remoteLineSuffix.set("#L")
         }
-        // }
     }
-}
\ No newline at end of file
+}
+
+tasks.register("dokka") {
+    group = "documentation"
+    description = "Generates Markdown API documentation."
+    dependsOn("dokkaGeneratePublicationGfm")
+}
diff --git a/gradle.properties b/gradle.properties
index 55a902b4..98461f08 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1 +1,2 @@
 org.gradle.warning.mode=all
+org.jetbrains.dokka.experimental.gradle.pluginMode=V2Enabled
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 62d4c053..02f06ab2 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 622ab64a..f900c206 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,8 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-bin.zip
+distributionSha256Sum=7988ed071b2a07900e2ec715fca15c6ab72bce6db433af301fa7fa7e9407bd24
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.6-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index fbd7c515..23d15a93 100755
--- a/gradlew
+++ b/gradlew
@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,81 +15,115 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
 
-APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
-CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+CLASSPATH="\\\"\\\""
 
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -98,88 +132,120 @@ Please set the JAVA_HOME variable in your environment to match the
 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.
+    JAVACMD=java
+    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.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
 fi
 
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
     # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
         fi
-        i=`expr $i + 1`
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
     done
-    case $i in
-        0) set -- ;;
-        1) set -- "$args0" ;;
-        2) set -- "$args0" "$args1" ;;
-        3) set -- "$args0" "$args1" "$args2" ;;
-        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
-    esac
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=`save "$@"`
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
index a9f778a7..5eed7ee8 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -13,8 +13,10 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 @rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +27,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -40,13 +43,13 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -54,49 +57,36 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
 :execute
 @rem Setup the command line
 
-set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+set CLASSPATH=
 
 
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal
diff --git a/src/main/kotlin/myaa/subkt/ass/parser.kt b/src/main/kotlin/myaa/subkt/ass/parser.kt
index 18004fa2..ff54a429 100644
--- a/src/main/kotlin/myaa/subkt/ass/parser.kt
+++ b/src/main/kotlin/myaa/subkt/ass/parser.kt
@@ -757,9 +757,9 @@ enum class Collisions(val value: String) {
 
 class CollisionsSerializer : ASSSerializer<Collisions> {
     override fun deserialize(s: String) =
-            when (s.toLowerCase()) {
-                Collisions.NORMAL.value.toLowerCase() -> Collisions.NORMAL
-                Collisions.REVERSE.value.toLowerCase() -> Collisions.REVERSE
+            when (s.lowercase()) {
+                Collisions.NORMAL.value.lowercase() -> Collisions.NORMAL
+                Collisions.REVERSE.value.lowercase() -> Collisions.REVERSE
                 else -> error("Invalid value for Collisions: $s")
             }
 
diff --git a/src/main/kotlin/myaa/subkt/tasks/muxtask.kt b/src/main/kotlin/myaa/subkt/tasks/muxtask.kt
index 212605c5..4cc3ec46 100644
--- a/src/main/kotlin/myaa/subkt/tasks/muxtask.kt
+++ b/src/main/kotlin/myaa/subkt/tasks/muxtask.kt
@@ -44,7 +44,7 @@ interface Filterable {
  * Filter files by file extension. Case-insensitive.
  */
 fun PatternFilterable.includeExtensions(vararg extensions: String) {
-    include { it.file.extension.toLowerCase() in extensions }
+    include { it.file.extension.lowercase() in extensions }
 }
 
 /**
@@ -972,7 +972,7 @@ open class Mux : PropertyTask() {
 
         // attachments
         toAttach.forEach {
-            val mime = mimeTypes[it.extension.toLowerCase()]
+            val mime = mimeTypes[it.extension.lowercase()]
             logger.lifecycle("Attaching ${it.name} (content-type: ${mime ?: "autodetected"})")
             mime?.let {
                 yield("--attachment-mime-type")
diff --git a/src/main/kotlin/myaa/subkt/tasks/tasks.kt b/src/main/kotlin/myaa/subkt/tasks/tasks.kt
index d41f9a89..7416f779 100644
--- a/src/main/kotlin/myaa/subkt/tasks/tasks.kt
+++ b/src/main/kotlin/myaa/subkt/tasks/tasks.kt
@@ -1726,10 +1726,10 @@ private class SSLSessionReuseFTPSClient(implicit: Boolean) : FTPSClient(implicit
                 method.setAccessible(true)
                 method.invoke(cache, String.format("%s:%s", socket.getInetAddress()
                         .hostName, socket.getPort().toString())
-                        .toLowerCase(Locale.ROOT), session)
+                        .lowercase(Locale.ROOT), session)
                 method.invoke(cache, String.format("%s:%s", socket.getInetAddress()
                         .hostAddress, socket.getPort().toString())
-                        .toLowerCase(Locale.ROOT), session)
+                        .lowercase(Locale.ROOT), session)
             } else {
                 throw error("Invalid SSL Session")
             }
diff --git a/src/main/kotlin/myaa/subkt/tasks/utils/fontvalidator.kt b/src/main/kotlin/myaa/subkt/tasks/utils/fontvalidator.kt
index 2bc9a32f..989382ff 100644
--- a/src/main/kotlin/myaa/subkt/tasks/utils/fontvalidator.kt
+++ b/src/main/kotlin/myaa/subkt/tasks/utils/fontvalidator.kt
@@ -202,10 +202,10 @@ private class FontCollection(fontFiles: Iterable<File>) {
         }
     }
 
-    val byFullName = fonts.flatMap { font -> font.exactNames.map { it.toLowerCase() to font } }.toMap()
+    val byFullName = fonts.flatMap { font -> font.exactNames.map { it.lowercase() to font } }.toMap()
 
     val byFamilyName = fonts
-            .flatMap { font -> font.families.map { it.toLowerCase() to font } }
+            .flatMap { font -> font.families.map { it.lowercase() to font } }
             .groupBy({ it.first }, { it.second })
 
     private val cache = mutableMapOf<State, FontMatch>()
@@ -227,7 +227,7 @@ private class FontCollection(fontFiles: Iterable<File>) {
             }
 
     fun match(state: State): FontMatch {
-        val s = state.copy(font = state.font.toLowerCase(), drawing = false)
+        val s = state.copy(font = state.font.lowercase(), drawing = false)
 
         return when (val f = cache[s]) {
             null -> {
diff --git a/src/test/kotlin/myaa/subkt/GradleCompatibilityTest.kt b/src/test/kotlin/myaa/subkt/GradleCompatibilityTest.kt
new file mode 100644
index 00000000..309ace1b
--- /dev/null
+++ b/src/test/kotlin/myaa/subkt/GradleCompatibilityTest.kt
@@ -0,0 +1,143 @@
+package myaa.subkt
+
+import myaa.subkt.ass.ASSFile
+import com.sun.net.httpserver.HttpServer
+import org.gradle.testkit.runner.GradleRunner
+import org.gradle.testkit.runner.TaskOutcome
+import org.junit.Assume.assumeTrue
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+import java.io.File
+import java.net.InetSocketAddress
+import java.util.Properties
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class GradleCompatibilityTest {
+    @get:Rule
+    val temporaryFolder = TemporaryFolder()
+
+    private fun project(script: String): File = temporaryFolder.newFolder().apply {
+        resolve("settings.gradle.kts").writeText("""
+            rootProject.name = "compatibility-test"
+            check(JavaVersion.current().majorVersion == "${System.getProperty("java.specification.version")}") {
+                "The consumer build must run on the same JDK as the compatibility tests"
+            }
+        """.trimIndent())
+        resolve("gradle.properties").writer().use { writer ->
+            Properties().apply {
+                setProperty("org.gradle.java.home", System.getProperty("java.home"))
+            }.store(writer, "Keep the consumer on the JDK being tested")
+        }
+        resolve("build.gradle.kts").writeText("""
+            import myaa.subkt.tasks.*
+            plugins { id("myaa.subkt") }
+            $script
+        """.trimIndent())
+    }
+
+    private fun run(project: File, vararg tasks: String) = GradleRunner.create()
+        .withProjectDir(project)
+        .withPluginClasspath()
+        .withArguments(*tasks, "--stacktrace", "--console=plain")
+        .build()
+
+    @Test
+    fun `subtitle task chain and torrent execute on the current JDK`() {
+        val project = project("""
+            subs {
+                episodes("01")
+                release("TV")
+                merge {
+                    from("dialogue.ass") { incrementLayer(10) }
+                }
+                swap { from(merge.item()) }
+                chapters { from(merge.item()) }
+                torrent {
+                    from(swap.item())
+                    trackers("https://tracker.invalid/announce")
+                }
+            }
+        """.trimIndent())
+        project.resolve("dialogue.ass").writeText("""
+            [Script Info]
+            ScriptType: v4.00+
+            PlayResX: 1920
+            PlayResY: 1080
+
+            [V4+ Styles]
+            Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
+            Style: Default,Arial,48,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,2,0,2,10,10,10,1
+
+            [Events]
+            Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
+            Dialogue: 0,0:00:01.00,0:00:03.00,Default,,0,0,0,,Karen{**-chan}
+            Comment: 0,0:00:05.00,0:00:06.00,Default,chptr,0,0,0,,Part A
+        """.trimIndent())
+
+        val result = run(project, "torrent.01", "chapters.01")
+        for (task in listOf("merge.01", "swap.01", "chapters.01", "torrent.01")) {
+            assertEquals(TaskOutcome.SUCCESS, result.task(":$task.TV")?.outcome, result.output)
+        }
+        val swapped = ASSFile(project.resolve("build/swap.01.TV.ass"))
+        assertEquals(10, swapped.events.lines.first().layer)
+        assertEquals("Karen{*}-chan{*}", swapped.events.lines.first().text)
+        assertTrue(project.resolve("build/chapters.01.TV.txt").readText().contains("CHAPTER02=00:00:05.000"))
+        assertTrue(project.resolve("build/torrent.01.TV.torrent").length() > 0)
+
+        val rerun = run(project, "torrent.01", "chapters.01")
+        assertEquals(TaskOutcome.UP_TO_DATE, rerun.task(":merge.01.TV")?.outcome)
+        assertEquals(TaskOutcome.UP_TO_DATE, rerun.task(":swap.01.TV")?.outcome)
+    }
+
+    @Test
+    fun `HTTP task runs with the Gradle Kotlin runtime`() {
+        val server = HttpServer.create(InetSocketAddress("127.0.0.1", 0), 0)
+        server.createContext("/test") { exchange ->
+            val response = "{\"ok\":true}".toByteArray()
+            exchange.responseHeaders.add("Content-Type", "application/json")
+            exchange.sendResponseHeaders(200, response.size.toLong())
+            exchange.responseBody.use { it.write(response) }
+        }
+        server.start()
+        try {
+            val project = project("""
+                val request by tasks.registering(HTTP::class) {
+                    host("127.0.0.1")
+                    https(false)
+                    port(${server.address.port})
+                    endpoint("/test")
+                }
+                tasks.register("verifyResponse") {
+                    dependsOn(request)
+                    doLast { check(request.get().responseJson.asJsonObject["ok"].asBoolean) }
+                }
+            """.trimIndent())
+            assertEquals(TaskOutcome.SUCCESS, run(project, "verifyResponse").task(":request")?.outcome)
+        } finally {
+            server.stop(0)
+        }
+    }
+
+    @Test
+    fun `automation executes a subprocess through Gradle services`() {
+        assumeTrue("The fake Aegisub executable requires a POSIX shell", File("/bin/sh").exists())
+        val project = project("""
+            tasks.register<Automation>("automate") {
+                aegisubCli(file("fake-aegisub").absolutePath)
+                from("input.ass")
+                out("output.ass")
+                macro("test macro")
+            }
+        """.trimIndent())
+        // This fixture substitutes for Aegisub so the test needs no external installation.
+        project.resolve("fake-aegisub").apply {
+            writeText("#!/bin/sh\n[ \"${'$'}3\" = \"test macro\" ] || exit 1\ncp \"${'$'}1\" \"${'$'}2\"\n")
+            setExecutable(true)
+        }
+        project.resolve("input.ass").writeText("test subtitle")
+        assertEquals(TaskOutcome.SUCCESS, run(project, "automate").task(":automate")?.outcome)
+        assertEquals("test subtitle", project.resolve("output.ass").readText())
+    }
+}
diff --git a/template/gradle/wrapper/gradle-wrapper.jar b/template/gradle/wrapper/gradle-wrapper.jar
index 62d4c053..02f06ab2 100644
Binary files a/template/gradle/wrapper/gradle-wrapper.jar and b/template/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/template/gradle/wrapper/gradle-wrapper.properties b/template/gradle/wrapper/gradle-wrapper.properties
index 622ab64a..f900c206 100644
--- a/template/gradle/wrapper/gradle-wrapper.properties
+++ b/template/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,8 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-bin.zip
+distributionSha256Sum=7988ed071b2a07900e2ec715fca15c6ab72bce6db433af301fa7fa7e9407bd24
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.6-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/template/gradlew b/template/gradlew
index fbd7c515..23d15a93 100755
--- a/template/gradlew
+++ b/template/gradlew
@@ -1,7 +1,7 @@
-#!/usr/bin/env sh
+#!/bin/sh
 
 #
-# Copyright 2015 the original author or authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,81 +15,115 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
 # Attempt to set APP_HOME
+
 # Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
 done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
 
-APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
-
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
 warn () {
     echo "$*"
-}
+} >&2
 
 die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
 nonstop=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
-  NONSTOP* )
-    nonstop=true
-    ;;
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
-CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+CLASSPATH="\\\"\\\""
 
 
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -98,88 +132,120 @@ Please set the JAVA_HOME variable in your environment to match the
 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.
+    JAVACMD=java
+    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.
-if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
 fi
 
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
 
 # For Cygwin or MSYS, switch paths to Windows format before running java
-if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
     # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
         fi
-        i=`expr $i + 1`
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
     done
-    case $i in
-        0) set -- ;;
-        1) set -- "$args0" ;;
-        2) set -- "$args0" "$args1" ;;
-        3) set -- "$args0" "$args1" "$args2" ;;
-        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
-    esac
 fi
 
-# Escape application args
-save () {
-    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
-    echo " "
-}
-APP_ARGS=`save "$@"`
 
-# Collect all arguments for the java command, following the shell quoting and substitution rules
-eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
 
 exec "$JAVACMD" "$@"
diff --git a/template/gradlew.bat b/template/gradlew.bat
index a9f778a7..5eed7ee8 100644
--- a/template/gradlew.bat
+++ b/template/gradlew.bat
@@ -13,8 +13,10 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 @rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +27,8 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -40,13 +43,13 @@ if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -54,49 +57,36 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windows variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-
 :execute
 @rem Setup the command line
 
-set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+set CLASSPATH=
 
 
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
 
 :end
 @rem End local scope for the variables with windows NT shell
-if "%ERRORLEVEL%"=="0" goto mainEnd
+if %ERRORLEVEL% equ 0 goto mainEnd
 
 :fail
 rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
 rem the _cmd.exe /c_ return code!
-if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
-exit /b 1
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
 
 :mainEnd
 if "%OS%"=="Windows_NT" endlocal