update_option( string $option, mixed $value, string|bool $autoload = null )

function update_option( $option, $value, $autoload = null ) {
    global $wpdb;

    if ( is_scalar( $option ) ) {
        $option = trim( $option );
    }

    if ( empty( $option ) ) {
        return false;
    }

    /*
     * Until a proper _deprecated_option() function can be introduced,
     * redirect requests to deprecated keys to the new, correct ones.
     */
    $deprecated_keys = array(
        'blacklist_keys'    => 'disallowed_keys',
        'comment_whitelist' => 'comment_previously_approved',
    );

    if ( isset( $deprecated_keys[ $option ] ) && ! wp_installing() ) {
        _deprecated_argument(
            __FUNCTION__,
            '5.5.0',
            sprintf(
                /* translators: 1: Deprecated option key, 2: New option key. */
                __( 'The "%1$s" option key has been renamed to "%2$s".' ),
                $option,
                $deprecated_keys[ $option ]
            )
        );
        return update_option( $deprecated_keys[ $option ], $value, $autoload );
    }

    wp_protect_special_option( $option );

    if ( is_object( $value ) ) {
        $value = clone $value;
    }

    $value     = sanitize_option( $option, $value );
    $old_value = get_option( $option );

    /**
     * Filters a specific option before its value is (maybe) serialized and updated.
     *
     * The dynamic portion of the hook name, `$option`, refers to the option name.
     *
     * @since 2.6.0
     * @since 4.4.0 The `$option` parameter was added.
     *
     * @param mixed  $value     The new, unserialized option value.
     * @param mixed  $old_value The old option value.
     * @param string $option    Option name.
     */
    $value = apply_filters( "pre_update_option_{$option}", $value, $old_value, $option );

    /**
     * Filters an option before its value is (maybe) serialized and updated.
     *
     * @since 3.9.0
     *
     * @param mixed  $value     The new, unserialized option value.
     * @param string $option    Name of the option.
     * @param mixed  $old_value The old option value.
     */
    $value = apply_filters( 'pre_update_option', $value, $option, $old_value );

    /*
     * If the new and old values are the same, no need to update.
     *
     * Unserialized values will be adequate in most cases. If the unserialized
     * data differs, the (maybe) serialized data is checked to avoid
     * unnecessary database calls for otherwise identical object instances.
     *
     * See https://core.trac.wordpress.org/ticket/38903
     */
    if ( $value === $old_value || maybe_serialize( $value ) === maybe_serialize( $old_value ) ) {
        return false;
    }

    /** This filter is documented in wp-includes/option.php */
    if ( apply_filters( "default_option_{$option}", false, $option, false ) === $old_value ) {
        return add_option( $option, $value, '', $autoload );
    }

    $serialized_value = maybe_serialize( $value );

    /**
     * Fires immediately before an option value is updated.
     *
     * @since 2.9.0
     *
     * @param string $option    Name of the option to update.
     * @param mixed  $old_value The old option value.
     * @param mixed  $value     The new option value.
     */
    do_action( 'update_option', $option, $old_value, $value );

    $update_args = array(
        'option_value' => $serialized_value,
    );

    if ( null !== $autoload ) {
        $update_args['autoload'] = wp_determine_option_autoload_value( $option, $value, $serialized_value, $autoload );
    } else {
        // Retrieve the current autoload value to reevaluate it in case it was set automatically.
        $raw_autoload = $wpdb->get_var( $wpdb->prepare( "SELECT autoload FROM $wpdb->options WHERE option_name = %s LIMIT 1", $option ) );
        $allow_values = array( 'auto-on', 'auto-off', 'auto' );
        if ( in_array( $raw_autoload, $allow_values, true ) ) {
            $autoload = wp_determine_option_autoload_value( $option, $value, $serialized_value, $autoload );
            if ( $autoload !== $raw_autoload ) {
                $update_args['autoload'] = $autoload;
            }
        }
    }

    $result = $wpdb->update( $wpdb->options, $update_args, array( 'option_name' => $option ) );
    if ( ! $result ) {
        return false;
    }

    $notoptions = wp_cache_get( 'notoptions', 'options' );

    if ( is_array( $notoptions ) && isset( $notoptions[ $option ] ) ) {
        unset( $notoptions[ $option ] );
        wp_cache_set( 'notoptions', $notoptions, 'options' );
    }

    if ( ! wp_installing() ) {
        if ( ! isset( $update_args['autoload'] ) ) {
            // Update the cached value based on where it is currently cached.
            $alloptions = wp_load_alloptions( true );

            if ( isset( $alloptions[ $option ] ) ) {
                $alloptions[ $option ] = $serialized_value;
                wp_cache_set( 'alloptions', $alloptions, 'options' );
            } else {
                wp_cache_set( $option, $serialized_value, 'options' );
            }
        } elseif ( in_array( $update_args['autoload'], wp_autoload_values_to_autoload(), true ) ) {
            // Delete the individual cache, then set in alloptions cache.
            wp_cache_delete( $option, 'options' );

            $alloptions = wp_load_alloptions( true );

            $alloptions[ $option ] = $serialized_value;
            wp_cache_set( 'alloptions', $alloptions, 'options' );
        } else {
            // Delete the alloptions cache, then set the individual cache.
            $alloptions = wp_load_alloptions( true );

            if ( isset( $alloptions[ $option ] ) ) {
                unset( $alloptions[ $option ] );
                wp_cache_set( 'alloptions', $alloptions, 'options' );
            }

            wp_cache_set( $option, $serialized_value, 'options' );
        }
    }

    /**
     * Fires after the value of a specific option has been successfully updated.
     *
     * The dynamic portion of the hook name, `$option`, refers to the option name.
     *
     * @since 2.0.1
     * @since 4.4.0 The `$option` parameter was added.
     *
     * @param mixed  $old_value The old option value.
     * @param mixed  $value     The new option value.
     * @param string $option    Option name.
     */
    do_action( "update_option_{$option}", $old_value, $value, $option );

    /**
     * Fires after the value of an option has been successfully updated.
     *
     * @since 2.9.0
     *
     * @param string $option    Name of the updated option.
     * @param mixed  $old_value The old option value.
     * @param mixed  $value     The new option value.
     */
    do_action( 'updated_option', $option, $old_value, $value );

    return true;
}