diff --git a/scripts/bump-version.py b/scripts/bump-version.py
index ddf414cd60a1114fc1d00462c05f55e7fa621523..0df1088bf028b17120311117c18a908c9cfe71fe 100755
--- a/scripts/bump-version.py
+++ b/scripts/bump-version.py
@@ -1,6 +1,10 @@
 #!/usr/bin/env python
 import sys
 
+raise RuntimeError("Many things have changed in the Python 3 port. " +
+                   "bump-version.py might require updates. " +
+                   "Only remove this error after careful checking!")
+
 if len(sys.argv) < 2:
   print("USAGE: python scripts/bump-version.py OST_VERSION")
   print("-> OST_VERSION is MAJOR.MINOR.PATCH (e.g. 1.9.1)")