In one of the previous versions, a user asked me to make it so that the subtitle input could be disabled on certain post types. I added some plugin options, but I didn't like how they were "check to disable". That's kind of backwards in my opinion. So I have switched them to "uncheck to disable", and have included an update routine that should switch your options should you have any saved.
If this doesn't work the way I had hoped (and tested), simply go to the plugin's options, check the post types you'd like to have support a subtitle input and re-save the options. The inputs will come back. None of your post data will be harmed.
Sorry for any inconvenience this might cause.