This version adds an option in the config editor that allows the extension to work even if there is no plus character in the To: address. The option is at “extensions.replyasoriginalrecipient.use_plus”. The default is true, meaning that the address has to contain a plus character. (That's the only change. The default behavior is exactly the same as in the previous version. If you aren't interested in this feature, there's no need to upgrade.)