Hi, currently I'm trying out the trial version of Jira Core and the latest version of your plugin.
I have activated the option Global Due Date Reminder and the emails are being sent correctly but the comments and the posts are not working.
What additional information can I give to help you debug this?
Currently i'm running Jira 7.6.3 on Windows 10 x64. I used the standalone install package of Jira so it's using the H2 database engine.