diff --git a/pom.xml b/pom.xml
index 3ea0cd9..c4f7d20 100644
--- a/pom.xml
+++ b/pom.xml
@@ -597,6 +597,11 @@
 			<artifactId>commons-text</artifactId>
 			<version>1.11.0</version>
 		</dependency>
+		<dependency>
+		  <groupId>org.apache.commons</groupId>
+		  <artifactId>commons-lang3</artifactId>
+		  <version>3.18.0</version>
+		</dependency>
 
 		<!-- LDAP -->
 		<dependency>
diff --git a/src/main/java/de/ids_mannheim/korap/authentication/LdapAuth3.java b/src/main/java/de/ids_mannheim/korap/authentication/LdapAuth3.java
index cfa2157..e2f4c59 100644
--- a/src/main/java/de/ids_mannheim/korap/authentication/LdapAuth3.java
+++ b/src/main/java/de/ids_mannheim/korap/authentication/LdapAuth3.java
@@ -214,9 +214,7 @@
             jlog.debug("{}: connect: successfull.", ldapConfig.useSSL ? "LDAPS" : "LDAP");
             }
         catch (LDAPException e) {
-            String fullStackTrace = org.apache.commons.lang.exception.ExceptionUtils
-                    .getFullStackTrace(e);
-            jlog.error("Connecting to LDAP Server: failed: '{}'!\n", fullStackTrace);
+            jlog.error("Connecting to LDAP Server: failed: '{}'!\n", e);
             
             ldapTerminate(lc);
             return new LdapAuth3Result(null, isTimeout(e) ? LDAP_AUTH_RTIMEOUT : LDAP_AUTH_RCONNECT);
diff --git a/src/main/java/de/ids_mannheim/korap/constant/AuthenticationScheme.java b/src/main/java/de/ids_mannheim/korap/constant/AuthenticationScheme.java
index e3068f7..8d1306b 100644
--- a/src/main/java/de/ids_mannheim/korap/constant/AuthenticationScheme.java
+++ b/src/main/java/de/ids_mannheim/korap/constant/AuthenticationScheme.java
@@ -1,6 +1,6 @@
 package de.ids_mannheim.korap.constant;
 
-import org.apache.commons.lang.WordUtils;
+import org.apache.commons.text.WordUtils;
 
 /**
  * Lists possible authentication schemes used in the Authorization
diff --git a/src/main/java/de/ids_mannheim/korap/constant/QueryType.java b/src/main/java/de/ids_mannheim/korap/constant/QueryType.java
index 5251bde..4967905 100644
--- a/src/main/java/de/ids_mannheim/korap/constant/QueryType.java
+++ b/src/main/java/de/ids_mannheim/korap/constant/QueryType.java
@@ -1,6 +1,6 @@
 package de.ids_mannheim.korap.constant;
 
-import org.apache.commons.lang.StringUtils;
+import org.apache.commons.lang3.StringUtils;
 
 public enum QueryType {
 
diff --git a/src/main/java/de/ids_mannheim/korap/constant/TokenType.java b/src/main/java/de/ids_mannheim/korap/constant/TokenType.java
index d238ac2..ac3f55c 100644
--- a/src/main/java/de/ids_mannheim/korap/constant/TokenType.java
+++ b/src/main/java/de/ids_mannheim/korap/constant/TokenType.java
@@ -1,6 +1,6 @@
 package de.ids_mannheim.korap.constant;
 
-import org.apache.commons.lang.StringUtils;
+import org.apache.commons.lang3.StringUtils;
 
 import de.ids_mannheim.korap.security.context.TokenContext;
 
diff --git a/src/main/java/de/ids_mannheim/korap/encryption/KustvaktEncryption.java b/src/main/java/de/ids_mannheim/korap/encryption/KustvaktEncryption.java
index 610f69c..1ac773b 100644
--- a/src/main/java/de/ids_mannheim/korap/encryption/KustvaktEncryption.java
+++ b/src/main/java/de/ids_mannheim/korap/encryption/KustvaktEncryption.java
@@ -7,7 +7,7 @@
 
 import org.apache.commons.codec.EncoderException;
 import org.apache.commons.codec.binary.Base64;
-import org.apache.commons.lang.RandomStringUtils;
+import org.apache.commons.lang3.RandomStringUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.mindrot.jbcrypt.BCrypt;
diff --git a/src/main/java/de/ids_mannheim/korap/encryption/RandomCodeGenerator.java b/src/main/java/de/ids_mannheim/korap/encryption/RandomCodeGenerator.java
index e6ff6e0..ba1abbe 100644
--- a/src/main/java/de/ids_mannheim/korap/encryption/RandomCodeGenerator.java
+++ b/src/main/java/de/ids_mannheim/korap/encryption/RandomCodeGenerator.java
@@ -10,7 +10,7 @@
 import java.util.stream.Collectors;
 
 import org.apache.commons.codec.binary.Base64;
-import org.apache.commons.lang.ArrayUtils;
+import org.apache.commons.lang3.ArrayUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.springframework.beans.factory.annotation.Autowired;
diff --git a/src/main/java/de/ids_mannheim/korap/utils/StringUtils.java b/src/main/java/de/ids_mannheim/korap/utils/StringUtils.java
index dd6259a..2272059 100644
--- a/src/main/java/de/ids_mannheim/korap/utils/StringUtils.java
+++ b/src/main/java/de/ids_mannheim/korap/utils/StringUtils.java
@@ -1,6 +1,6 @@
 package de.ids_mannheim.korap.utils;
 
-import org.apache.commons.lang.StringEscapeUtils;
+import org.apache.commons.text.StringEscapeUtils;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
@@ -119,11 +119,11 @@
     }
 
     public static String normalizeHTML (String value) {
-        return StringEscapeUtils.escapeHtml(value);
+        return StringEscapeUtils.escapeHtml4(value);
     }
 
     public static String decodeHTML (String value) {
-        return StringEscapeUtils.unescapeHtml(value);
+        return StringEscapeUtils.unescapeHtml4(value);
     }
 
     public static String getDocSigle (String textSigle) {