I found this post, but it's 5 years old, so I thought I'd ask again to see if anything has changed.
I have built an email signature in HTML and applied it as a mail flow rule to append to all emails. It works well for new chains. However, if someone emails me and I reply, it appends the "disclaimer" to the very bottom of the message and makes it look like their signature.
Is there a way to append this "inline"?
Maybe I misunderstood your requirement, but I have to confirm:
Did you want to make the disclaimer show only one time, or add the disclaimer under each newest reply?
For the former, I think you could add an exception in the rule(Except if the subject or body in message includes the disclaimer keywords or phrases) to throw away additional disclaimers.
For the later, it seems that there isn't any configuration to add the disclaimer under each newest reply in Exchange Server, however, you could setup a signature for your mailboxes so that you could reply emails with the signature which includes the disclaimer. The similar thread is for your reference: How to add Disclaimer for replied Emails