diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 3e4a382..6f48b65 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -9,3 +9,7 @@ updates:
     directory: "/" # Location of package manifests
     schedule:
       interval: "weekly"
+    ignore:
+      # Gradle 9 requires Java 17 to run. CI runs Gradle on Java 8 and 11.
+      - dependency-name: "gradle-wrapper"
+        update-types: ["version-update:semver-major"]
diff --git a/build.gradle b/build.gradle
index 0d8eabd..c375258 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,7 +1,18 @@
+buildscript {
+  dependencies {
+    // jreleaser 1.26.0 pulls older versions with known advisories. Remove once it pulls these.
+    constraints {
+      classpath 'com.fasterxml.jackson.core:jackson-databind:2.22.3'
+      classpath 'org.apache.httpcomponents.client5:httpclient5:5.6.3'
+      classpath 'org.codehaus.plexus:plexus-utils:3.6.1'
+    }
+  }
+}
+
 plugins {
   id 'java-library'
   id 'maven-publish'
-  id 'org.jreleaser' version '1.21.0'
+  id 'org.jreleaser' version '1.26.0'
   id "com.diffplug.spotless" version "6.13.0"
 }
 
@@ -38,11 +49,11 @@ dependencies {
   implementation 'org.slf4j:slf4j-api:2.0.17'
   implementation 'org.jetbrains:annotations:26.1.0'
 
-  // Logback classic 1.3.x is compatible with java 8 - only needed for tests
   testImplementation 'cloud.eppo:eppo-sdk-framework:0.1.0-SNAPSHOT:tests'
-  testImplementation 'ch.qos.logback:logback-classic:1.3.16'
-  testImplementation platform('org.junit:junit-bom:5.11.4')
+  testImplementation 'org.slf4j:slf4j-simple:2.0.17'
+  testImplementation platform('org.junit:junit-bom:5.14.4')
   testImplementation 'org.junit.jupiter:junit-jupiter'
+  testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
   testImplementation 'com.github.tomakehurst:wiremock-jre8:2.35.2'
   testImplementation 'org.mockito:mockito-core:4.11.0'
   testImplementation 'com.squareup.okhttp3:okhttp:4.12.0'
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 249e583..02f06ab 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 bd64439..d3f0219 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,7 @@
-#Thu Jun 06 13:59:33 PDT 2024
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+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 1b6c787..23d15a9 100755
--- a/gradlew
+++ b/gradlew
@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       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/.
@@ -80,13 +82,11 @@ do
     esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${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"'
+# 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
@@ -114,7 +114,7 @@ case "$( uname )" in                #(
   NONSTOP* )        nonstop=true ;;
 esac
 
-CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+CLASSPATH="\\\"\\\""
 
 
 # Determine the Java command to use to start the JVM.
@@ -133,22 +133,29 @@ 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.
 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 $MAX_FD"
     esac
@@ -193,18 +200,28 @@ if "$cygwin" || "$msys" ; then
     done
 fi
 
-# 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.
+
+# 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" \
-        org.gradle.wrapper.GradleWrapperMain \
+        -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.
diff --git a/gradlew.bat b/gradlew.bat
index ac1b06f..5eed7ee 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 execute
+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
 
@@ -56,32 +59,34 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 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
 
 :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 %*
+"%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/test/resources/logback-test.xml b/src/test/resources/logback-test.xml
deleted file mode 100644
index 9f6f580..0000000
--- a/src/test/resources/logback-test.xml
+++ /dev/null
@@ -1,11 +0,0 @@
-<configuration>
-    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-        <encoder>
-            <pattern>%d{HH:mm:ss.SSS} %-5level - %msg%n</pattern>
-        </encoder>
-    </appender>
-
-    <root level="DEBUG">
-        <appender-ref ref="STDOUT" />
-    </root>
-</configuration>
diff --git a/src/test/resources/logback.xml b/src/test/resources/logback.xml
deleted file mode 100644
index 5c07584..0000000
--- a/src/test/resources/logback.xml
+++ /dev/null
@@ -1,11 +0,0 @@
-<configuration>
-    <root level="DEBUG">
-        <AppenderRef ref="STDOUT"/>
-    </root>
-
-    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
-        <encoder>
-            <pattern>%d{HH:mm:ss.SSS} %-5level - %msg%n</pattern>
-        </encoder>
-    </appender>
-</configuration>
diff --git a/src/test/resources/simplelogger.properties b/src/test/resources/simplelogger.properties
new file mode 100644
index 0000000..599224d
--- /dev/null
+++ b/src/test/resources/simplelogger.properties
@@ -0,0 +1,6 @@
+org.slf4j.simpleLogger.defaultLogLevel=debug
+org.slf4j.simpleLogger.showDateTime=true
+org.slf4j.simpleLogger.dateTimeFormat=HH:mm:ss.SSS
+org.slf4j.simpleLogger.showThreadName=false
+org.slf4j.simpleLogger.showLogName=false
+org.slf4j.simpleLogger.logFile=System.out