diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
index bf065be55..cc75b785f 100644
--- a/.github/workflows/gradle.yml
+++ b/.github/workflows/gradle.yml
@@ -9,7 +9,7 @@ jobs:
 
     strategy:
       matrix:
-        java: [ '11', '17', '21' ]
+        java: [ '11', '17', '21', '23' ]
 
     steps:
     - uses: actions/checkout@v4
diff --git a/build.gradle b/build.gradle
index 054782af8..9553f2780 100644
--- a/build.gradle
+++ b/build.gradle
@@ -13,7 +13,7 @@ plugins {
   id 'java-library'
 
   // To create a fat jar build/libs/...-all.jar, run: ./gradlew shadowJar
-  id 'com.github.johnrengelman.shadow' version '8.1.1'
+  id 'com.gradleup.shadow' version '8.3.5'
 
   // Error Prone linter
   id('net.ltgt.errorprone') version '4.1.0'
@@ -24,13 +24,14 @@ plugins {
 
 repositories {
   mavenCentral()
-  maven { url 'https://oss.sonatype.org/content/repositories/snapshots/' }
+  maven { url = 'https://oss.sonatype.org/content/repositories/snapshots/' }
 }
 
-ext.errorproneVersion = '2.31.0'
-
 ext {
+  errorproneVersion = '2.36.0'
   isJava11orHigher = JavaVersion.current() >= JavaVersion.VERSION_11
+  isJava17orHigher = JavaVersion.current() >= JavaVersion.VERSION_17
+  isJava21orHigher = JavaVersion.current() >= JavaVersion.VERSION_21
 }
 
 dependencies {
@@ -39,9 +40,6 @@ dependencies {
   implementation 'org.apache.commons:commons-text:1.13.0'
   implementation 'org.plumelib:reflection-util:1.1.4'
 
-  compileOnly "com.google.errorprone:error_prone_annotations:${errorproneVersion}"
-  errorprone("com.google.errorprone:error_prone_core:${errorproneVersion}")
-
   testImplementation 'org.junit.jupiter:junit-jupiter-api:5.11.4'
   testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine'
 }
@@ -94,7 +92,12 @@ if (isJava11orHigher) {
   }
 }
 
-/// Error Prone linter
+// Error Prone linter
+
+dependencies {
+  compileOnly "com.google.errorprone:error_prone_annotations:${errorproneVersion}"
+  errorprone("com.google.errorprone:error_prone_core:${errorproneVersion}")
+}
 
 tasks.withType(JavaCompile).configureEach {
   // "-processing" avoids javac warning "No processor claimed any of these annotations".
@@ -108,15 +111,16 @@ tasks.withType(JavaCompile).configureEach {
     disable('AnnotateFormatMethod') // Error Prone doesn't know about Checker Framework @FormatMethod
     disable('UseCorrectAssertInTests') // https://github.com/typetools/checker-framework/issues/3345
   }
+  options.errorprone.enabled = isJava17orHigher
 }
 
-/// Checker Framework pluggable type-checking
+// Checker Framework pluggable type-checking
 
 apply plugin: 'org.checkerframework'
 
 if (true) {
   // Use the released version of the EISOP Checker Framework.
-  ext.checkerFrameworkVersion = '3.42.0-eisop3'
+  ext.checkerFrameworkVersion = '3.42.0-eisop5'
 } else {
   // To use a snapshot version of the EISOP Checker Framework.
   // TODO: Change the above test to false to use a snapshot.
@@ -168,7 +172,7 @@ checkerFramework {
   ]
 }
 
-/// Javadoc
+// Javadoc
 
 // Turn Javadoc warnings into errors.
 javadoc {
@@ -186,7 +190,7 @@ javadoc {
 check.dependsOn javadoc
 
 task javadocWeb(type: Javadoc) {
-  description 'Upload API documentation to website.'
+  description = 'Upload API documentation to website.'
   source = sourceSets.main.allJava
   destinationDir = file("/cse/web/research/plumelib/${project.name}/api")
   classpath = project.sourceSets.main.compileClasspath
@@ -225,10 +229,10 @@ task requireJavadoc(type: JavaExec) {
 check.dependsOn requireJavadoc
 javadocWeb.dependsOn requireJavadoc
 
-/// Emacs support
+// Emacs support
 
 /* Make Emacs TAGS table */
 task tags(type: Exec) {
-  description 'Run etags to create an Emacs TAGS table'
+  description = 'Run etags to create an Emacs TAGS table'
   commandLine 'bash', '-c', "find src/ -name '*.java' | sort | xargs etags"
 }
diff --git a/gradle/mavencentral.gradle b/gradle/mavencentral.gradle
index 702522e91..cfef2ccd2 100644
--- a/gradle/mavencentral.gradle
+++ b/gradle/mavencentral.gradle
@@ -1,9 +1,9 @@
 // REQUIREMENTS to make a release:
 //  * Your ~/.gradle/gradle.properties file must contain:
-//     ossrhUsername=YOUR_USER_NAME_HERE
-//     ossrhPassword=YOUR_PASSWORD_HERE
+//     SONATYPE_NEXUS_USERNAME=...
+//     SONATYPE_NEXUS_PASSWORD=...
 
-// To make a release (run on any filesystem, except the last step):
+// To make a release (run on any filesystem, except the `javadocWeb` step):
 //  * git pull
 //  * In ../build.gradle, ensure that "To use a snapshot version" is not enabled.
 //  * Update the version number in ../README.md and in this file (multiple times in each).
@@ -20,8 +20,11 @@
 apply plugin: 'maven-publish'
 apply plugin: 'signing'
 
-group 'org.plumelib'
-version '2.0.3'
+group = 'org.plumelib'
+version = '2.0.3'
+ext {
+  packageName = 'options'
+}
 
 final isSnapshot = version.contains('SNAPSHOT')
 
@@ -41,12 +44,12 @@ publishing {
       pom {
         name = 'Plume-lib Options'
         description = 'Command-line option processing for Java.'
-        url = 'https://github.com/plume-lib/options'
+        url = "https://github.com/plume-lib/${packageName}"
 
         scm {
-          connection = 'scm:git:git@github.com:plume-lib/options.git'
-          developerConnection = 'scm:git:git@github.com:plume-lib/options.git'
-          url = 'git@github.com:plume-lib/options.git'
+          connection = "scm:git:git@github.com:plume-lib/${packageName}.git"
+          developerConnection = "scm:git:git@github.com:plume-lib/${packageName}.git"
+          url = "git@github.com:plume-lib/${packageName}.git"
         }
 
         licenses {
@@ -74,8 +77,8 @@ publishing {
             : project.properties.getOrDefault('RELEASE_REPOSITORY_URL', 'https://oss.sonatype.org/service/local/staging/deploy/maven2/')
             )
         credentials {
-          username = project.properties.get('ossrhUsername')
-          password = project.properties.get('ossrhPassword')
+          username = project.properties.get('SONATYPE_NEXUS_USERNAME')
+          password = project.properties.get('SONATYPE_NEXUS_PASSWORD')
         }
       }
     }
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index e2847c820..cea7a793a 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
diff --git a/gradlew b/gradlew
index f5feea6d6..f3b75f3b0 100755
--- a/gradlew
+++ b/gradlew
@@ -86,8 +86,7 @@ done
 # 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 "${APP_HOME:-./}" > /dev/null && printf '%s
-' "$PWD" ) || exit
+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
diff --git a/src/main/java/org/plumelib/options/Options.java b/src/main/java/org/plumelib/options/Options.java
index 662f1db51..72f914fde 100644
--- a/src/main/java/org/plumelib/options/Options.java
+++ b/src/main/java/org/plumelib/options/Options.java
@@ -374,7 +374,7 @@ class OptionInfo {
 
     /**
      * Long argument name. Uses '-' or '_' to separate words, depending on the value of {@link
-     * useDashes}.
+     * #useDashes}.
      */
     String longName;
 
diff --git a/src/main/java/org/plumelib/options/OptionsDoclet.java b/src/main/java/org/plumelib/options/OptionsDoclet.java
index 9290e4422..1f43b7c69 100644
--- a/src/main/java/org/plumelib/options/OptionsDoclet.java
+++ b/src/main/java/org/plumelib/options/OptionsDoclet.java
@@ -242,9 +242,9 @@ public OptionsDoclet() {
     // this.options = options;
   }
 
-  ///////////////////////////////////////////////////////////////////////////
-  /// Doclet-specific methods
-  ///
+  // //////////////////////////////////////////////////////////////////////
+  // Doclet-specific methods
+  //
 
   @Override
   public void init(Locale locale, Reporter reporter) {
@@ -338,9 +338,9 @@ public boolean run(DocletEnvironment denv) {
     return OK;
   }
 
-  ///////////////////////////////////////////////////////////////////////////
-  /// Javadoc command-line options
-  ///
+  // //////////////////////////////////////////////////////////////////////
+  // Javadoc command-line options
+  //
 
   // The doclet cannot use the Options class itself because  Javadoc specifies its own way of
   // handling command-line arguments.
@@ -588,9 +588,9 @@ private void printError(String msg) {
     reporter.print(Diagnostic.Kind.ERROR, msg);
   }
 
-  ///////////////////////////////////////////////////////////////////////////
-  /// File IO methods
-  ///
+  // //////////////////////////////////////////////////////////////////////
+  // File IO methods
+  //
 
   /**
    * Write the output of this doclet to the correct file.
@@ -685,9 +685,9 @@ private String newDocFileText() throws Exception {
     return b.toString();
   }
 
-  ///////////////////////////////////////////////////////////////////////////
-  /// HTML and Javadoc processing methods
-  ///
+  // //////////////////////////////////////////////////////////////////////
+  // HTML and Javadoc processing methods
+  //
 
   /**
    * Returns the fields defined by the given type.
@@ -1143,9 +1143,9 @@ public Void visitSee(SeeTree node, StringBuilder sb) {
 
   }
 
-  ///////////////////////////////////////////////////////////////////////////
-  /// Signature string methods
-  ///
+  // //////////////////////////////////////////////////////////////////////
+  // Signature string methods
+  //
 
   /**
    * Returns true if the given element kind is a type, i.e., a class, enum, interface, or annotation
@@ -1190,9 +1190,9 @@ public static boolean isTypeElement(Element element) {
     }
   }
 
-  ///////////////////////////////////////////////////////////////////////////
-  /// Getters and Setters
-  ///
+  // //////////////////////////////////////////////////////////////////////
+  // Getters and Setters
+  //
 
   /**
    * Returns true if the output format is Javadoc, false if the output format is HTML.