Inline comments in macro content: Confluence 6.13.x vs 7.3.x

Hello,
In newer versions of Confluence (7.3.1) when a user adds a comment to content that is rendered by an xhtml-macro they get a warning that the comment cannot be inlined but it will be saved as a page comment. That works.ME_comment_warning

In older versions of Confluence (6.13.0) the user gets a warning that they cannot add an inline comment at all. There is no mention of adding it as a page comment:


If the user ignores the warning and clicks Save for their comment it does not appear to do anything (the browser developer console will show a HTTP 412 response from the REST API: rest/inlinecomments/1.0/comments)

Is this something that would ever be backported as a bug fix to older Confluence Server versions or should we tell our customers to upgrade?

I’m guessing that some bug record was used to fix this in newer Confluence versions but I can’t find it. I did find this bug, sort of related, for 6.13.0, where it is said that inline comments in macros is by design: https://jira.atlassian.com/browse/CONFSERVER-58176

Thanks!