diff --git a/core/src/net/sf/openrocket/startup/Application.java b/core/src/net/sf/openrocket/startup/Application.java
index cbccb9a4e..f298cccfc 100644
--- a/core/src/net/sf/openrocket/startup/Application.java
+++ b/core/src/net/sf/openrocket/startup/Application.java
@@ -22,7 +22,7 @@ public final class Application {
 	private static Injector injector;
 
 	// Supported Java Runtime Environment versions in which OR is allowed to run (e.g. '11' for Java 11)
-	public static int[] SUPPORTED_JRE_VERSIONS = {11, 12, 13};
+	public static int[] SUPPORTED_JRE_VERSIONS = {11};
 	
 	/**
 	 * Return whether to use additional safety code checks.
diff --git a/swing/src/net/sf/openrocket/startup/SwingStartup.java b/swing/src/net/sf/openrocket/startup/SwingStartup.java
index 92270957e..c95860878 100644
--- a/swing/src/net/sf/openrocket/startup/SwingStartup.java
+++ b/swing/src/net/sf/openrocket/startup/SwingStartup.java
@@ -107,7 +107,7 @@ public class SwingStartup {
 				if (IntStream.of(Application.SUPPORTED_JRE_VERSIONS).noneMatch(c -> c == version)) {
 					String title = "Unsupported Java version";
 					String message1 = "Unsupported Java version: %s";
-					String message2 = "Supported versions: %s";
+					String message2 = "Supported version(s): %s";
 					String message3 = "Please change the Java Runtime Environment version or install OpenRocket using a packaged installer.";
 
 					StringBuilder message = new StringBuilder();