diff --git a/Assets/Mirror/Tests/NetworkWriterTest.cs b/Assets/Mirror/Tests/NetworkWriterTest.cs
index e6d48d45d..e1520f784 100644
--- a/Assets/Mirror/Tests/NetworkWriterTest.cs
+++ b/Assets/Mirror/Tests/NetworkWriterTest.cs
@@ -486,6 +486,22 @@ public void TestReadingTruncatedString()
             Assert.Throws<System.IO.EndOfStreamException>(() => reader.ReadString());
         }
 
+        [Test]
+        public void TestStringBinaryCompat()
+        {
+            NetworkWriter writer = new NetworkWriter();
+            writer.Write("");
+            writer.Write("short string");
+            writer.Write(string.Join("0", new string[100000]));
+            byte[] data = writer.ToArray();
+            byte[] expect = new byte[]{1,0,1,12,115,104,111,114,116,32,115,116,114,105,110,103,1,159,141,6};
+            Assert.That(data.Length, Is.EqualTo(100019));
+            for (int i = 0; i < expect.Length; i++)
+                Assert.That(data[i], Is.EqualTo(expect[i]), $"index {i}");
+            for (int i = expect.Length; i < data.Length; i++)
+                Assert.That(data[i], Is.EqualTo(48), $"index {i}");
+        }
+
         [Test]
         public void TestToArray()
         {