diff --git a/cas-client-core/pom.xml b/cas-client-core/pom.xml
index e8d0a31..8e6420b 100644
--- a/cas-client-core/pom.xml
+++ b/cas-client-core/pom.xml
@@ -29,9 +29,9 @@
 
     <dependencies>
         <dependency>
-            <groupId>commons-lang</groupId>
-            <artifactId>commons-lang</artifactId>
-            <version>2.6</version>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>3.4</version>
         </dependency>
 
         <dependency>
diff --git a/cas-client-core/src/main/java/org/jasig/cas/client/configuration/BaseConfigurationStrategy.java b/cas-client-core/src/main/java/org/jasig/cas/client/configuration/BaseConfigurationStrategy.java
index 79872c5..dbf4e89 100644
--- a/cas-client-core/src/main/java/org/jasig/cas/client/configuration/BaseConfigurationStrategy.java
+++ b/cas-client-core/src/main/java/org/jasig/cas/client/configuration/BaseConfigurationStrategy.java
@@ -18,8 +18,8 @@
  */
 package org.jasig.cas.client.configuration;
 
-import org.apache.commons.lang.BooleanUtils;
-import org.apache.commons.lang.math.NumberUtils;
+import org.apache.commons.lang3.BooleanUtils;
+import org.apache.commons.lang3.math.NumberUtils;
 import org.jasig.cas.client.util.CommonUtils;
 import org.jasig.cas.client.util.ReflectUtils;
 import org.slf4j.Logger;
diff --git a/cas-client-core/src/main/java/org/jasig/cas/client/session/SingleSignOutHandler.java b/cas-client-core/src/main/java/org/jasig/cas/client/session/SingleSignOutHandler.java
index 162c7b9..4efc018 100644
--- a/cas-client-core/src/main/java/org/jasig/cas/client/session/SingleSignOutHandler.java
+++ b/cas-client-core/src/main/java/org/jasig/cas/client/session/SingleSignOutHandler.java
@@ -28,7 +28,7 @@ import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 
 import org.apache.commons.codec.binary.Base64;
-import org.apache.commons.lang.StringUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.jasig.cas.client.Protocol;
 import org.jasig.cas.client.configuration.ConfigurationKeys;
 import org.jasig.cas.client.util.CommonUtils;