bbp_past_edit_lock( string $post_date_gmt )

function bbp_past_edit_lock( $post_date_gmt ) {

	// Assume editing is allowed
	$retval = false;

	// Bail if empty date
	if ( ! empty( $post_date_gmt ) ) {

		// Period of time
		$lockable  = '+' . get_option( '_bbp_edit_lock', '5' ) . ' minutes';

		// Now
		$cur_time  = current_time( 'timestamp', true );

		// Add lockable time to post time
		$lock_time = strtotime( $lockable, strtotime( $post_date_gmt ) );

		// Compare
		if ( $cur_time >= $lock_time ) {
			$retval = true;
		}
	}

	return apply_filters( 'bbp_past_edit_lock', (bool) $retval, $cur_time, $lock_time, $post_date_gmt );
}