I got a weird error when I tried to deploy. I updated to the latest Python Launcher code, and tried again, and it said I need to rollback.
$ appcfg.py rollback .
10:54 AM Application: kaon-log
10:54 AM Rolling back the update.
Error 404: --- begin server output ---
<html><head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<title>404 Not Found</title>
</head>
<body text=#000000 bgcolor=#ffffff>
<h1>Error: Not Found</h1>
<h2>The requested URL <code>/api/appversion/rollback?app_id=kaon-log&force_rollback=0&version=58</code> was not found on this server.</h2>
<h2></h2>
</body></html>
--- end server output ---