You don't have to wait for the next version release. You can add the exact same hook in the same location manually. Once the update is released, you can update without any issue.

Open this file:

wp-content/plugins/wpforo/wpforo.php

Find this line:

if( $this->post->get_option_union_first_post($current_object) ) $args = true;
$current_object = $this->post->get_posts( $args, $current_object);

And add the extra "hook line" between them like this:

if( $this->post->get_option_union_first_post($current_object) ) $args = true;
$args = apply_filters('wpforo_post_list_args', $args);
$current_object = $this->post->get_posts( $args, $current_object);

Then add the updated code for reversing replies order:

https://wpforo.com/community/how-to-and-troubleshooting-2/how-to-sort-posts-in-a-thread-oldest-first/#post-15418

Dear plugin developers, I also really need the last comment to be the first in the topic. To be like on YouTube. In this case, the description of the topic 1 comment was always on top for SEO.

@alexas,

If you just need to keep the first post (topic first post) on top of the topic on all pages you can enable the corresponding option in Dashboard > Forums > Settings > Topics & Posts Tab. You can enable it for each forum layout separately:

https://wpforo.com/wp-content/uploads/2020/12/wpForo-stick-first-post-on-top-in-topics.png

As per the hook for sorting replies, it comes very soon. Probably tomorrow.

Unfortunately the peace of code is moved to a core file. So there is no way to do this customization. In upcoming version, we'll add a new hook in the core file and let you do this change. I don't have any ETA yet. Just update this topic, once the next version is released.