diff --git a/build.gradle b/build.gradle
index 63a7f51..22c08f0 100644
--- a/build.gradle
+++ b/build.gradle
@@ -4,7 +4,7 @@ plugins {
 }
 
 wrapper {
-    gradleVersion = "${project.property('gradle.wrapper.version')}"
+    gradleVersion = libs.versions.gradle.get()
     distributionType = Wrapper.DistributionType.ALL
 }
 
diff --git a/gradle.properties b/gradle.properties
index 10201e6..dc9d3fc 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,5 +1,5 @@
 group = org.xbib
 name = standardnumber
-version = 1.2.2
+version = 2.0.0
 
-gradle.wrapper.version = 7.3.2
+org.gradle.warning.mode = ALL
diff --git a/gradle/compile/java.gradle b/gradle/compile/java.gradle
index 9c8798d..5f46bfb 100644
--- a/gradle/compile/java.gradle
+++ b/gradle/compile/java.gradle
@@ -6,13 +6,13 @@ java {
 }
 
 compileJava {
-    sourceCompatibility = JavaVersion.VERSION_11
-    targetCompatibility = JavaVersion.VERSION_11
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
 }
 
 compileTestJava {
-    sourceCompatibility = JavaVersion.VERSION_11
-    targetCompatibility = JavaVersion.VERSION_11
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
 }
 
 jar {
@@ -24,6 +24,7 @@ jar {
 task sourcesJar(type: Jar, dependsOn: classes) {
     classifier 'sources'
     from sourceSets.main.allSource
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
 }
 
 task javadocJar(type: Jar, dependsOn: javadoc) {
@@ -35,9 +36,11 @@ artifacts {
 }
 
 tasks.withType(JavaCompile) {
-    options.compilerArgs << '-Xlint:all'
+    options.compilerArgs.add('-Xlint:all,-exports')
+    options.encoding = 'UTF-8'
 }
 
-javadoc {
+tasks.withType(Javadoc) {
     options.addStringOption('Xdoclint:none', '-quiet')
+    options.encoding = 'UTF-8'
 }
diff --git a/gradle/test/junit5.gradle b/gradle/test/junit5.gradle
index bbfa201..d7a8070 100644
--- a/gradle/test/junit5.gradle
+++ b/gradle/test/junit5.gradle
@@ -1,12 +1,8 @@
-
-def junitVersion = project.hasProperty('junit.version')?project.property('junit.version'):'5.7.1'
-def hamcrestVersion = project.hasProperty('hamcrest.version')?project.property('hamcrest.version'):'2.2'
-
 dependencies {
-    testImplementation "org.junit.jupiter:junit-jupiter-api:${junitVersion}"
-    testImplementation "org.junit.jupiter:junit-jupiter-params:${junitVersion}"
-    testImplementation "org.hamcrest:hamcrest-library:${hamcrestVersion}"
-    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:${junitVersion}"
+    testImplementation libs.junit.jupiter.api
+    testImplementation libs.junit.jupiter.params
+    testImplementation libs.hamcrest
+    testRuntimeOnly libs.junit.jupiter.engine
 }
 
 test {
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 7454180..249e583 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 ac0b842..8fad3f5 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.3.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index 1b6c787..a69d9cb 100755
--- a/gradlew
+++ b/gradlew
@@ -205,6 +205,12 @@ set -- \
         org.gradle.wrapper.GradleWrapperMain \
         "$@"
 
+# 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..53a6b23 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -14,7 +14,7 @@
 @rem limitations under the License.
 @rem
 
-@if "%DEBUG%" == "" @echo off
+@if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
 @rem  Gradle startup script for Windows
@@ -25,7 +25,7 @@
 if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
-if "%DIRNAME%" == "" set DIRNAME=.
+if "%DIRNAME%"=="" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
@@ -40,7 +40,7 @@ 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.
@@ -75,13 +75,15 @@ set CLASSPATH=%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/settings.gradle b/settings.gradle
index 89f4110..de84a01 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -1 +1,28 @@
-rootProject.name = name
+pluginManagement {
+    repositories {
+        mavenLocal()
+        mavenCentral {
+            metadataSources {
+                mavenPom()
+                artifact()
+                ignoreGradleMetadataRedirection()
+            }
+        }
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolutionManagement {
+    versionCatalogs {
+        libs {
+            version('gradle', '7.5.1')
+            version('groovy', '3.0.10')
+            version('junit', '5.9.2')
+            library('junit-jupiter-api', 'org.junit.jupiter', 'junit-jupiter-api').versionRef('junit')
+            library('junit-jupiter-params', 'org.junit.jupiter', 'junit-jupiter-params').versionRef('junit')
+            library('junit-jupiter-engine', 'org.junit.jupiter', 'junit-jupiter-engine').versionRef('junit')
+            library('hamcrest', 'org.hamcrest', 'hamcrest-library').version('2.2')
+            library('junit4', 'junit', 'junit').version('4.13.2')
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/org/xbib/standardnumber/checksum/DihedralGroup.java b/src/main/java/org/xbib/standardnumber/checksum/DihedralGroup.java
index cef4031..cbca79f 100644
--- a/src/main/java/org/xbib/standardnumber/checksum/DihedralGroup.java
+++ b/src/main/java/org/xbib/standardnumber/checksum/DihedralGroup.java
@@ -31,6 +31,8 @@ public class DihedralGroup implements Digit {
             {4, 2, 8, 6, 5, 7, 3, 9, 0, 1}, {2, 7, 9, 3, 8, 0, 6, 4, 1, 5},
             {7, 0, 4, 6, 9, 1, 3, 2, 5, 8}};
 
+    public DihedralGroup() {
+    }
 
     @Override
     public String encode(String digits) {
diff --git a/src/main/java/org/xbib/standardnumber/checksum/LuhnMOD10.java b/src/main/java/org/xbib/standardnumber/checksum/LuhnMOD10.java
index 6332ffa..e611c38 100644
--- a/src/main/java/org/xbib/standardnumber/checksum/LuhnMOD10.java
+++ b/src/main/java/org/xbib/standardnumber/checksum/LuhnMOD10.java
@@ -5,6 +5,9 @@ package org.xbib.standardnumber.checksum;
  */
 public class LuhnMOD10 implements Digit {
 
+    public LuhnMOD10() {
+    }
+
     @Override
     public String encode(String digits) {
         return digits + compute(digits);
diff --git a/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD1110.java b/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD1110.java
index 29070d1..a7745a9 100644
--- a/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD1110.java
+++ b/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD1110.java
@@ -9,6 +9,9 @@ public class MOD1110 implements Digit {
 
     private static final String ALPHABET = "0123456789";
 
+    public MOD1110() {
+    }
+
     @Override
     public String encode(String digits) {
         int c = compute(digits);
diff --git a/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD112.java b/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD112.java
index 03243be..a8fc7cd 100644
--- a/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD112.java
+++ b/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD112.java
@@ -7,6 +7,9 @@ import org.xbib.standardnumber.checksum.Digit;
  */
 public class MOD112 implements Digit {
 
+    public MOD112() {
+    }
+
     @Override
     public String encode(String digits) {
         int c = compute(digits);
diff --git a/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD3736.java b/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD3736.java
index 73ebcbd..9183758 100644
--- a/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD3736.java
+++ b/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD3736.java
@@ -9,6 +9,9 @@ public class MOD3736 implements Digit {
 
     private static final String ALPHABET = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
+    public MOD3736() {
+    }
+
     @Override
     public String encode(String digits) {
         int c = compute(digits);
diff --git a/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD9710.java b/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD9710.java
index e81886b..ea476e2 100644
--- a/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD9710.java
+++ b/src/main/java/org/xbib/standardnumber/checksum/iso7064/MOD9710.java
@@ -12,6 +12,9 @@ public class MOD9710 implements Digit {
 
     private static final BigDecimal CONSTANT_97 = new BigDecimal(97);
 
+    public MOD9710() {
+    }
+
     @Override
     public String encode(String digits) {
         int c = compute(digits);