You would need to create a custom role, should be possible.
Take a look at these to get you started:
https://codex.bbpress.org/bbpress-user-roles-and-capabilities/
Custom Capabilities
@luisannet I am stuck with the same problem with my site. Could you please help me out?
Beyond @netweb’s links above, what help do you need?
My problem is that I need that all users should be able to start a thread and only the user who started the thread and admin/moderator/keymaster should be able to reply. What permissions should I set on the user?
@tajender
You’d need to modify
wp-content/bbpress/templats/default/bbpress/form-reply.php
create a directory on your theme called ‘bbpress’
ie wp-content/%your-theme-name%/bbpress
find
wp-content/bbpress/templats/default/bbpress/form-reply.php
Make a copy of this file, and put in in the directory called bbpress that you created above, so you end up with
wp-content/%your-theme-name%/bbpress/loop-single-reply.php
bbPress will now use this template instead of the original
you should really do this inside a child theme
Functions files and child themes – explained !
but if you do it in your main theme, keep a copy of what youb have done as updates are likely to overwrite
The you would need to modify line 20
<?php if ( bbp_current_user_can_access_create_reply_form() ) : ?>
to put in a check to see if it’s current user
It’s too near xmas, and I have too much else on to write and test the code but it will involve bbp_get_currect_user and the topic author $user_id
