diff --git a/pom.xml b/pom.xml
index 7d23399..67d1996 100644
--- a/pom.xml
+++ b/pom.xml
@@ -202,7 +202,7 @@
 		<dependency>
 			<groupId>org.junit.jupiter</groupId>
 			<artifactId>junit-jupiter-engine</artifactId>
-			<version>5.10.0-M1</version>
+			<version>5.10.0-RC1</version>
 			<scope>test</scope>
 		</dependency>
 	</dependencies>
diff --git a/src/main/java/de/svenkubiak/jpushover/apis/Message.java b/src/main/java/de/svenkubiak/jpushover/apis/Message.java
index d6e943a..be2ea9a 100644
--- a/src/main/java/de/svenkubiak/jpushover/apis/Message.java
+++ b/src/main/java/de/svenkubiak/jpushover/apis/Message.java
@@ -225,13 +225,15 @@ public class Message implements API {
     }
 
     /**
+     * Adds a ttl to the Pushover message
      * 
      * @param ttl Seconds until this message should be automatically removed from the device. Needs to be positive
-     * @see https://pushover.net/api#ttl
      * @return Message instance
      */
     public Message withTTL(int ttl) {
-        body.put(Param.TTL.toString(), Integer.toString(ttl));
+        Validate.checkArgument(ttl > 0, "TTL must be a positive value");
+        
+        body.put(Param.TTL.toString(), String.valueOf(ttl));
         return this;
     }
 
diff --git a/src/test/java/jpushover/apis/MessageTests.java b/src/test/java/jpushover/apis/MessageTests.java
index c8a3fdb..8685328 100644
--- a/src/test/java/jpushover/apis/MessageTests.java
+++ b/src/test/java/jpushover/apis/MessageTests.java
@@ -58,6 +58,18 @@ public class MessageTests {
         assertTrue(message.getValue(Param.USER.toString()).equals(value));
     }
     
+    @Test
+    void testWithTTL() {
+        //given
+        int ttl = 5;
+        
+        //when
+        Message message = JPushover.messageAPI().withTTL(5);
+        
+        //then
+        assertTrue(message.getValue(Param.TTL.toString()).equals(String.valueOf(ttl)));
+    }
+    
     @Test
     void testWithRetry() {
         //given