Reply Monitor is compatible with the latest version of Thunderbird now.

Change name from Reply Manager to Reply Monitor to avoid trademark infringement.

Bug fix:
The subject of the expect-reply message is now correctly displayed after the calendar event is refreshed.

New function:
You can now choose if you want CCs and BCCs to reply your email. Note that at this moment, the setting is global, meaning once set it will be applied to all emails you are going to send as well as those that you have already sent out. If you want different settings to be applied to individual emails, let me know.

Fixed the following bugs:
1. When any of the three toolbarbuttons is not on the mail window's custom toolbar, there will be an error making the message pane (header and content) completely blank.
2. Experimental locale caused some problems with some people.

Change:
Now this extension has its own preference window. You can access it in the Addons window. Hopefully this will fix some people's problem with prefpane in previous versions.