Hi guys how can I hide Board Style: option and revers it to default
ACP>Templates & Styles>Themes>YOUR THEME>Allowed User Groups>Admins
That will prevent everyone except the admins to change or use that theme. If someone is not allowed on that list, they won't see the theme in the "Board Style" dropdown option in UCP.
Also, be sure force your default theme on everyone so they don't see the old theme.
No problem. Glad I could help and thanks for the +rep.