We have just rolled out the preview version of the “reply to comment” feature. Responding to MantisHub notifications is now as simple as replying from within your favorite email client. Such replies will be added as comments/notes on the issue.
It is also very easy to involve others in the conversations by just adding them to the to/cc field of the reply. This way as email participants are having the conversations, the conversation messages are being recorded on the issue.
For more details about the feature checkout the feature documentation.
Looking forward for your feedback.