diff --git a/build.gradle b/build.gradle
index eb570e0..866ac6c 100644
--- a/build.gradle
+++ b/build.gradle
@@ -13,7 +13,7 @@ buildscript {
 
   dependencies {
   	// usage: gradle dependencyUpdates -Drevision=release
-    classpath 'com.github.ben-manes:gradle-versions-plugin:0.20.0'
+    classpath 'com.github.ben-manes:gradle-versions-plugin:0.21.0'
   }
 }
 
@@ -21,21 +21,21 @@ ext {
     
     lib_antlr = "org.antlr:antlr4:4.7.2"
     
-    lib_commons_collections4 = 'org.apache.commons:commons-collections4:4.2'
-    lib_commons_lang3 = 'org.apache.commons:commons-lang3:3.8.1'
-    lib_guava = 'com.google.guava:guava:27.0.1-jre'
+    lib_commons_collections4 = 'org.apache.commons:commons-collections4:4.3'
+    lib_commons_lang3 = 'org.apache.commons:commons-lang3:3.9'
+    lib_guava = 'com.google.guava:guava:27.1-jre'
     lib_jackson_databind = 'com.fasterxml.jackson.core:jackson-databind:2.9.8'
     
-    lib_log4j2_api = 'org.apache.logging.log4j:log4j-api:2.11.1'
-    lib_log4j2_core = 'org.apache.logging.log4j:log4j-core:2.11.1'
-    lib_log4j2_slf4j_impl = 'org.apache.logging.log4j:log4j-slf4j-impl:2.11.1'
+    lib_log4j2_api = 'org.apache.logging.log4j:log4j-api:2.11.2'
+    lib_log4j2_core = 'org.apache.logging.log4j:log4j-core:2.11.2'
+    lib_log4j2_slf4j_impl = 'org.apache.logging.log4j:log4j-slf4j-impl:2.11.2'
     
     lib_primitive_collections='org.lucares:primitiveCollections:0.1.20190217091430'
     
-    lib_spring_boot_log4j2='org.springframework.boot:spring-boot-starter-log4j2:2.1.2.RELEASE'
-    lib_spring_boot_mustache='org.springframework.boot:spring-boot-starter-mustache:2.1.2.RELEASE'
-    lib_spring_boot_test='org.springframework.boot:spring-boot-starter-test:2.1.2.RELEASE'
-    lib_spring_boot_web='org.springframework.boot:spring-boot-starter-web:2.1.2.RELEASE'
+    lib_spring_boot_log4j2='org.springframework.boot:spring-boot-starter-log4j2:2.1.4.RELEASE'
+    lib_spring_boot_mustache='org.springframework.boot:spring-boot-starter-mustache:2.1.4.RELEASE'
+    lib_spring_boot_test='org.springframework.boot:spring-boot-starter-test:2.1.4.RELEASE'
+    lib_spring_boot_web='org.springframework.boot:spring-boot-starter-web:2.1.4.RELEASE'
     
     eclipseAccessRestrictions = [
         'org.eclipse.jdt.launching.JRE_CONTAINER': [
@@ -118,5 +118,5 @@ allprojects {
 }
 
 wrapper {
-    gradleVersion = '5.2.1'
+    gradleVersion = '5.4'
 }
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 87b738c..5c2d1cf 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 44e7c4d..5f1b120 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-5.2.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.4-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index af6708f..b0d6d0a 100755
--- a/gradlew
+++ b/gradlew
@@ -1,5 +1,21 @@
 #!/usr/bin/env sh
 
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
 ##############################################################################
 ##
 ##  Gradle start up script for UN*X
@@ -28,7 +44,7 @@ APP_NAME="Gradle"
 APP_BASE_NAME=`basename "$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"'
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD="maximum"
diff --git a/gradlew.bat b/gradlew.bat
index 0f8d593..15e1ee3 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -1,3 +1,19 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      http://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
 @if "%DEBUG%" == "" @echo off
 @rem ##########################################################################
 @rem
@@ -14,7 +30,7 @@ set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
 @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS="-Xmx64m"
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
 
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome