diff --git a/Assets/Mirror/CompilerSymbols/PreprocessorDefine.cs b/Assets/Mirror/CompilerSymbols/PreprocessorDefine.cs
index 2e973531a..89867c1e8 100644
--- a/Assets/Mirror/CompilerSymbols/PreprocessorDefine.cs
+++ b/Assets/Mirror/CompilerSymbols/PreprocessorDefine.cs
@@ -42,7 +42,8 @@ public static void AddDefineSymbols()
                 "MIRROR_55_0_OR_NEWER",
                 "MIRROR_57_0_OR_NEWER",
                 "MIRROR_58_0_OR_NEWER",
-                "MIRROR_65_0_OR_NEWER"
+                "MIRROR_65_0_OR_NEWER",
+                "MIRROR_66_0_OR_NEWER"
             };
 
             // only touch PlayerSettings if we actually modified it.
diff --git a/ProjectSettings/ProjectSettings.asset b/ProjectSettings/ProjectSettings.asset
index b72d55b51..f516f07a1 100644
--- a/ProjectSettings/ProjectSettings.asset
+++ b/ProjectSettings/ProjectSettings.asset
@@ -576,7 +576,7 @@ 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;MIRROR_39_0_OR_NEWER;MIRROR_40_0_OR_NEWER;MIRROR_41_0_OR_NEWER;MIRROR_42_0_OR_NEWER;MIRROR_43_0_OR_NEWER;MIRROR_44_0_OR_NEWER;MIRROR_46_0_OR_NEWER;MIRROR_47_0_OR_NEWER;MIRROR_53_0_OR_NEWER;MIRROR_55_0_OR_NEWER;MIRROR_57_0_OR_NEWER;MIRROR_58_0_OR_NEWER;MIRROR_65_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;MIRROR_40_0_OR_NEWER;MIRROR_41_0_OR_NEWER;MIRROR_42_0_OR_NEWER;MIRROR_43_0_OR_NEWER;MIRROR_44_0_OR_NEWER;MIRROR_46_0_OR_NEWER;MIRROR_47_0_OR_NEWER;MIRROR_53_0_OR_NEWER;MIRROR_55_0_OR_NEWER;MIRROR_57_0_OR_NEWER;MIRROR_58_0_OR_NEWER;MIRROR_65_0_OR_NEWER;MIRROR_66_0_OR_NEWER
   platformArchitecture: {}
   scriptingBackend: {}
   il2cppCompilerConfiguration: {}