diff --git a/misc/product_codes.txt b/misc/product_codes.txt
new file mode 100644
index 0000000..dbb4e54
--- /dev/null
+++ b/misc/product_codes.txt
@@ -0,0 +1,14 @@
+Bremen calling Installer Upgrade Codes:
+======================================
+
+Test: 1C7FA3E4-BAB9-4911-9348-73094357FC7C
+Prod: 81A329F1-C663-48DA-9E15-DAF19F99B5AE
+
+Product codes v1.2.2.3:
+
+Test: 6F89CBAA-2189-456F-A347-0C0158325B61
+Prod: 0ED342DD-DC00-4CE4-8348-96BB3AB726B1
+
+Note:
+If you want the MSI to "upgrade" from one version to the other, the
+upgrade code must stay the same and the product code must change.
\ No newline at end of file