If the edit history is showing on your Forum Discussion post like the screenshot below. You can hide it by adding the CSS code below. 

1. Go to BuddyBoss > Theme Options

2. Under Custom Codes, enable CSS

3. Append the following:

.bbp-topic-revision-log {

    display: none;

}

4. Save changes.

Note: Any modifications are considered as custom work already. Know more about our Support policy here: https://www.buddyboss.com/support-policy/