diff --git a/build.gradle b/build.gradle
index 94bf9e5..c59194f 100644
--- a/build.gradle
+++ b/build.gradle
@@ -13,7 +13,7 @@ buildscript {
   }
 
   dependencies {
-  	// usage: gradlew dependencyUpdates -Drevision=release
+    // usage: gradlew dependencyUpdates -Drevision=release
     classpath 'com.github.ben-manes:gradle-versions-plugin:0.33.0'
   }
 }
@@ -23,7 +23,7 @@ ext {
     javaVersion=14
     
     version_log4j2= '2.13.3' // keep in sync with spring-boot-starter-log4j2
-    version_spring = '2.3.4.RELEASE'
+    version_spring = '2.3.5.RELEASE'
     version_junit = '5.7.0'
     version_junit_platform = '1.7.0'
     
@@ -59,44 +59,44 @@ ext {
  * The shared configuration for all sub-projects:
  */
 subprojects {
-	apply plugin: 'java-library'
-	apply plugin: 'eclipse'
-	
-	compileJava.options.encoding = 'UTF-8'
+  apply plugin: 'java-library'
+  apply plugin: 'eclipse'
+  
+  compileJava.options.encoding = 'UTF-8'
 
-	// java compatibility version
-	sourceCompatibility = javaVersion
-	
-	configurations {
-		tests
-	}
-	
-	// the repositories for external depenencies
-	repositories {
-		maven { 
-		  url 'https://repo.lucares.de/'
-		  content { includeGroup "org.lucares" }
-        }
-		mavenCentral(content: { excludeGroup "org.lucares" })
-		jcenter{
-		  content { excludeGroup "org.lucares" }
-		}
-	}
-	
-	test{
-		useJUnitPlatform {
+  // java compatibility version
+  sourceCompatibility = javaVersion
+  
+  configurations {
+    tests
+  }
+  
+  // the repositories for external depenencies
+  repositories {
+    maven { 
+      url 'https://repo.lucares.de/'
+      content { includeGroup "org.lucares" }
+    }
+    mavenCentral(content: { excludeGroup "org.lucares" })
+    jcenter{
+      content { excludeGroup "org.lucares" }
+    }
+  }
+  
+  test{
+    useJUnitPlatform {
         includeEngines 'junit-jupiter'
         excludeEngines 'junit-vintage'
     }
-	}
-	
-	// dependencies that all sub-projects have 
-	dependencies {
+  }
+  
+  // dependencies that all sub-projects have 
+  dependencies {
     testImplementation("org.junit.jupiter:junit-jupiter-engine:${version_junit}")
     testImplementation "org.junit.jupiter:junit-jupiter-params:${version_junit}"  // for @ParameterizedTest
     testImplementation "org.junit.platform:junit-platform-launcher:${version_junit_platform}" // needed by eclipse
   }
-	
+  
    task eclipseSettings(type: Copy) {
       from ("${rootProject.projectDir}/eclipse/") {
           include '**/*.prefs'
@@ -106,8 +106,8 @@ subprojects {
   }
   tasks.eclipseJdt.dependsOn eclipseSettings
   tasks.cleanEclipseJdt.dependsOn cleanEclipseSettings
-	
-	eclipse {
+  
+  eclipse {
         classpath {
             file {
                 whenMerged {
@@ -115,7 +115,7 @@ subprojects {
                         def container = entries.find { it.path.contains path }
                         if (container != null) {
                             container.accessRules.addAll(restrictions)
-                        }    
+                        }
                     }
                 }
             }