diff --git a/.github/workflows/security-test-workflow.yml b/.github/workflows/security-test-workflow.yml
index 127962210..1c5781d38 100644
--- a/.github/workflows/security-test-workflow.yml
+++ b/.github/workflows/security-test-workflow.yml
@@ -12,7 +12,7 @@ jobs:
   build:
     strategy:
       matrix:
-        java: [ 11, 17 ]
+        java: [ 11, 17, 21 ]
     # Job name
     name: Build and test Alerting
     # This job runs on Linux
diff --git a/.github/workflows/test-workflow.yml b/.github/workflows/test-workflow.yml
index 2ef1196b9..ebc4c2cec 100644
--- a/.github/workflows/test-workflow.yml
+++ b/.github/workflows/test-workflow.yml
@@ -21,7 +21,7 @@ jobs:
       WORKING_DIR: ${{ matrix.working_directory }}.
     strategy:
       matrix:
-        java: [11, 17]
+        java: [11, 17, 21]
     # Job name
     name: Build Alerting with JDK ${{ matrix.java }} on Linux
     # This job runs on Linux
@@ -69,7 +69,7 @@ jobs:
       WORKING_DIR: ${{ matrix.working_directory }}.
     strategy:
       matrix:
-        java: [11, 17]
+        java: [11, 17, 21]
         os: [ windows-latest, macos-latest ]
         include:
           - os: windows-latest
diff --git a/build-tools/merged-coverage.gradle b/build-tools/merged-coverage.gradle
index 83fa44d20..a5bb24894 100644
--- a/build-tools/merged-coverage.gradle
+++ b/build-tools/merged-coverage.gradle
@@ -5,7 +5,7 @@
 
 allprojects {
     plugins.withId('jacoco') {
-        jacoco.toolVersion = '0.8.7'
+        jacoco.toolVersion = '0.8.11'
         // For some reason this dependency isn't getting setup automatically by the jacoco plugin
         tasks.withType(JacocoReport) { 
             dependsOn tasks.withType(Test)
diff --git a/build.gradle b/build.gradle
index defcf229b..c920a85e4 100644
--- a/build.gradle
+++ b/build.gradle
@@ -39,7 +39,7 @@ buildscript {
 }
 
 plugins {
-    id 'com.netflix.nebula.ospackage' version "11.0.0"
+    id 'com.netflix.nebula.ospackage' version "11.5.0"
     id "com.dorongold.task-tree" version "1.5"
 }
 
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index c1962a79e..d64cd4917 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..3499ded5c 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-8.1.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
 networkTimeout=10000
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index aeb74cbb4..1aa94a426 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.
@@ -141,7 +145,7 @@ if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
         # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC3045
+        # shellcheck disable=SC2039,SC3045
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
@@ -149,7 +153,7 @@ if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
       '' | soft) :;; #(
       *)
         # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
-        # shellcheck disable=SC3045
+        # shellcheck disable=SC2039,SC3045
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac
@@ -198,11 +202,11 @@ fi
 # 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 $GRADLE_OPTS can contain fragments of
-#     shell script including quotes and variable substitutions, so put them in
-#     double quotes to make sure that they get re-expanded; and
-#   * put everything else in single quotes, so that it's not re-expanded.
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_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" \