diff --git a/packaging/dotnet-core/prepare.py b/packaging/dotnet-core/prepare.py
index 29710d75..3ba7d7d0 100755
--- a/packaging/dotnet-core/prepare.py
+++ b/packaging/dotnet-core/prepare.py
@@ -17,7 +17,7 @@ MACOS = [
   # --------------------- ----------------- #
   # Runtime ID            Codename          #
   # --------------------- ----------------- #
-  ( 'osx-x64',            'sierra'          ),
+  ( 'osx-x64',            'mojave'          ),
   # --------------------- ----------------- #
 ]