Jeff Starr

Override WordPress “automatically close comments” option and leave comments open on any individual posts.
Want to keep comments open on a few old posts? This plugin is for you. Here’s how it works:
In the WordPress Discussion Settings, there is an option called “Automatically close comments on posts older than” whatever specified number of days. When this setting is enabled, comments will be disabled on any posts that are past the deadline, whatever “x” number of days.
What WordPress is missing is a simple way to override that global option on a per-post basis. That’s exactly what this plugin does. For any post that is past the comment deadline, this plugin will display a small meta box on the “Edit Post” screen for each post. There you can check the box to enable comments on the post. Comments will then remain open for that post indefinitely, until the box is unchecked or the plugin is uninstalled.
Note: The override meta box will not be displayed if the post is not past the comment deadline (whatever “x” number of days).
Check out the screenshot below to get a better idea.
Features
<ul>
<li>Clean, secure code</li>
<li>Written according to the WP API</li>
<li>Simple, lightweight, and flexible</li>
<li>Localized and translation ready</li>
<li>Cleans up after itself when uninstalled</li>
</ul>
For more details about how it works, visit the <a href="https://wordpress.org/plugins/override-comment-options/#installation" rel="ugc">Installation docs</a>.
Privacy
This plugin does not collect or store any user data. It does not set any cookies, and it does not connect to any third-party locations. Thus, this plugin does not affect user privacy in any way.
Override Comment Options is developed and maintained by <a href="https://x.com/perishable" rel="nofollow ugc">Jeff Starr</a>, 15-year <a href="https://plugin-planet.com/" rel="nofollow ugc">WordPress developer</a> and <a href="https://books.perishablepress.com/" rel="nofollow ugc">book author</a>.

Override Comment Options

Enables per-post override of "Automatically close comments on posts older than" option in the WP Discussion Settings.

Robin W

Pascal Casier

Adds an option to the Discussion meta box to use a bbPress topic instead of WordPress comments, and displays that topic beneath the post on your site.
You can let the plugin create a new topic for you in the forum of your choice, or specify an existing topic to attach to the post. 
A topic can be attached to as many posts as you’d like, but only one topic can currently be attached to a post.

Post Comments as bbPress Topics

Great support!

I use it to link my Learndash to bbpress forums so that my students can discuss a lesson, either under it or in a forum topic. Really practical, glad that this plugin exists!

Really practical, glad that this plugin exists!

Replace the comments on your WordPress blog posts with topics from an integrated bbPress install

Override Comment Options vs Post Comments as bbPress Topics