WordPress at a glance
function is not described

update_blog_option() WP 3.0.0

Update an option for a particular blog.

No Hooks.

Return

true/false. True on success, false on failure.

Usage

update_blog_option( $id, $option, $value, $deprecated );
$id(int) (required)
The blog id.
$option(string) (required)
The option key.
$value(mixed) (required)
The option value.
$deprecated(mixed)
Not used.
Default: null

Code of update blog option: wp-includes/ms-blogs.php VER 5.1.1

<?php
function update_blog_option( $id, $option, $value, $deprecated = null ) {
	$id = (int) $id;

	if ( null !== $deprecated ) {
		_deprecated_argument( __FUNCTION__, '3.1.0' );
	}

	if ( get_current_blog_id() == $id ) {
		return update_option( $option, $value );
	}

	switch_to_blog( $id );
	$return = update_option( $option, $value );
	restore_current_blog();

	return $return;
}