diff --git a/Assets/Mirror/CompilerSymbols/PreprocessorDefine.cs b/Assets/Mirror/CompilerSymbols/PreprocessorDefine.cs
index 790c6653f..2d3266f35 100644
--- a/Assets/Mirror/CompilerSymbols/PreprocessorDefine.cs
+++ b/Assets/Mirror/CompilerSymbols/PreprocessorDefine.cs
@@ -29,7 +29,8 @@ public static void AddDefineSymbols()
                 "MIRROR_35_0_OR_NEWER",
                 "MIRROR_35_1_OR_NEWER",
                 "MIRROR_37_0_OR_NEWER",
-                "MIRROR_38_0_OR_NEWER"
+                "MIRROR_38_0_OR_NEWER",
+                "MIRROR_39_0_OR_NEWER"
             };
 
             // only touch PlayerSettings if we actually modified it.
diff --git a/ProjectSettings/ProjectSettings.asset b/ProjectSettings/ProjectSettings.asset
index 1bec6aa11..05e8f804f 100644
--- a/ProjectSettings/ProjectSettings.asset
+++ b/ProjectSettings/ProjectSettings.asset
@@ -545,7 +545,7 @@ PlayerSettings:
   webGLThreadsSupport: 0
   webGLWasmStreaming: 0
   scriptingDefineSymbols:
-    1: MIRROR;MIRROR_17_0_OR_NEWER;MIRROR_18_0_OR_NEWER;MIRROR_24_0_OR_NEWER;MIRROR_26_0_OR_NEWER;MIRROR_27_0_OR_NEWER;MIRROR_28_0_OR_NEWER;MIRROR_29_0_OR_NEWER;MIRROR_30_0_OR_NEWER;MIRROR_30_5_2_OR_NEWER;MIRROR_32_1_2_OR_NEWER;MIRROR_32_1_4_OR_NEWER;MIRROR_35_0_OR_NEWER;MIRROR_35_1_OR_NEWER;MIRROR_37_0_OR_NEWER;MIRROR_38_0_OR_NEWER
+    1: MIRROR;MIRROR_17_0_OR_NEWER;MIRROR_18_0_OR_NEWER;MIRROR_24_0_OR_NEWER;MIRROR_26_0_OR_NEWER;MIRROR_27_0_OR_NEWER;MIRROR_28_0_OR_NEWER;MIRROR_29_0_OR_NEWER;MIRROR_30_0_OR_NEWER;MIRROR_30_5_2_OR_NEWER;MIRROR_32_1_2_OR_NEWER;MIRROR_32_1_4_OR_NEWER;MIRROR_35_0_OR_NEWER;MIRROR_35_1_OR_NEWER;MIRROR_37_0_OR_NEWER;MIRROR_38_0_OR_NEWER;MIRROR_39_0_OR_NEWER
   platformArchitecture: {}
   scriptingBackend: {}
   il2cppCompilerConfiguration: {}