OMG, you MySQL server is very old. ok, No problem, use this:

ALTER TABLE `wp_wpforo_subscribes`
CHANGE COLUMN `user_name` `user_name` VARCHAR(99) NOT NULL DEFAULT '' COLLATE 'utf8mb4_unicode_ci' AFTER `active`,
CHANGE COLUMN `user_email` `user_email` VARCHAR(99) NOT NULL DEFAULT '' COLLATE 'utf8mb4_unicode_ci' AFTER `user_name`;

I just removed the subscription table line in the main SQL for Emoji. You can use that without the SQL in post above.

thank you again !

Your last request functions on my database (my MySQL Version is 5.5.55).

But do you know why my emojy is still replaced by "???" as you can see on the copy screen.

Have you done this?

https://wpforo.com/community/faq/emoji-does-not-work-errors-topic-add-error-and-reply-failed/

Once all SQLs is executed, create a new topic and post and test it. If it still doesn't work you should upgrade your database to 5.6 and make sure all users char-set is utf8mb.

Please note, we're not the Emoji developers and charset creators. This issue doesn't have direct relation to wpForo. Emoji is global project and it has multibit structure. If it doesn't work on your website it means whether the database can't save this content or the PC/Browser can't display it. wpForo can't affect this, so wpForo support also can't fix this.