diff --git a/server/build.gradle b/server/build.gradle
index faf03d4..3ac4ccc 100644
--- a/server/build.gradle
+++ b/server/build.gradle
@@ -12,10 +12,10 @@ plugins {
   id 'checkstyle'
 }
 
-// Build and run the project with Java 17
+// Build and run the project with Java 21
 java {
   toolchain {
-    languageVersion = JavaLanguageVersion.of(17)
+    languageVersion = JavaLanguageVersion.of(21)
   }
 }
 
@@ -29,7 +29,7 @@ repositories {
 // External dependencies that our application utilizes
 dependencies {
   // Javalin, a simple web framework for Java
-  implementation 'io.javalin:javalin:5.6.3'
+  implementation 'io.javalin:javalin:6.3.0'
 
   // Jackson, a JSON library for Java
   implementation 'com.fasterxml.jackson.core:jackson-databind:2.17.2'
diff --git a/server/src/main/java/umm3601/Server.java b/server/src/main/java/umm3601/Server.java
index 2c2b6eb..c5506db 100644
--- a/server/src/main/java/umm3601/Server.java
+++ b/server/src/main/java/umm3601/Server.java
@@ -5,7 +5,6 @@
 import io.javalin.Javalin;
 import io.javalin.http.InternalServerErrorResponse;
 import io.javalin.http.staticfiles.Location;
-import io.javalin.plugin.bundled.RouteOverviewPlugin;
 
 public class Server {
 
@@ -78,7 +77,7 @@ private Javalin configureJavalin() {
       // This adds a Javalin plugin that will list all of the
       // routes/endpoints that we add below on a page reachable
       // via the "/api" path.
-      config.plugins.register(new RouteOverviewPlugin("/api"));
+      config.bundledPlugins.enableRouteOverview("/api");
     });
 
     // This catches any uncaught exceptions thrown in the server
diff --git a/server/src/main/java/umm3601/user/User.java b/server/src/main/java/umm3601/user/User.java
index 7c63a00..8fe3e64 100644
--- a/server/src/main/java/umm3601/user/User.java
+++ b/server/src/main/java/umm3601/user/User.java
@@ -26,4 +26,18 @@ public class User {
   public int age;
   public String company;
   public String email;
+
+  // Having some kind of `toString()` allows us to print `User`s,
+  // which can be useful/necessary in error handling. This only
+  // returns the name, but it could be extended to return more or
+  // all of the fields combined into a single string.
+  //
+  // The other option would be to return `_id`, but that can be
+  // `null` if we're trying to add a new `User` to the database
+  // that doesn't yet have an `_id`, so returning `name` seemed
+  // the better bet.
+  @Override
+  public String toString() {
+    return name;
+  }
 }