If you go to the website for SerialSticker you'll find that the developer sold his apps to app4mac, which already publishes RapidoSerial:

<http://www.eagle-of-liberty.com/index_en.php>

I wrote to app4mac about some suggestions for new features but didn't receive a reply.

I have since discovered License Keeper, which seems to have all the features I suggested to app4mac. RapidoSerial is free, however what's the point if it doesn't do what I need and there's no support?