WooCommerce Subscriptions Conditional Reminder Email Ability

functions.php

/**
 * Add a new "Subscription Reminders" tab in the Product Data panel
 * for Simple Subscription products only.
 */
add_filter( 'woocommerce_product_data_tabs', 'wcs_add_subscriptions_reminders_tab_simple' );
function wcs_add_subscriptions_reminders_tab_simple( $tabs ) {

    // Only add this tab for subscription products (excluding variable-subscriptions).
    // The "show_if_subscription" class ensures the tab is visible only for "simple subscription".
    $tabs['wcs_sub_reminders_simple'] = array(
        'label'  => __( 'Subscription Reminders', 'your-textdomain' ),
        'target' => 'wcs_sub_reminders_options_simple',
        'class'  => array( 'show_if_subscription' ),
        'priority' => 90,
    );

    return $tabs;
}

/**
 * Render the content for the "Subscription Reminders" tab in Simple Subscriptions.
 */
add_action( 'woocommerce_product_data_panels', 'wcs_add_sub_reminders_tab_content_simple' );
function wcs_add_sub_reminders_tab_content_simple() {
    echo '<div id="wcs_sub_reminders_options_simple" class="panel woocommerce_options_panel hidden">';

    // We'll use WooCommerce's helper function to output checkboxes.
    // Each meta key is unique to a specific reminder email type.
    woocommerce_wp_checkbox( array(
        'id'          => '_include_customer_notification_manual_trial_expiration',
        'label'       => __( 'Manual Trial Expiration reminder email', 'your-textdomain' ),
        'description' => __( 'Enable sending the "Manual Trial Expiration" reminder for this product.', 'your-textdomain' ),
    ) );

    woocommerce_wp_checkbox( array(
        'id'          => '_include_customer_notification_auto_trial_expiration',
        'label'       => __( 'Auto Trial Expiration reminder email', 'your-textdomain' ),
        'description' => __( 'Enable sending the "Auto Trial Expiration" reminder for this product.', 'your-textdomain' ),
    ) );

    woocommerce_wp_checkbox( array(
        'id'          => '_include_customer_notification_manual_renewal',
        'label'       => __( 'Manual Renewal reminder email', 'your-textdomain' ),
        'description' => __( 'Enable sending the "Manual Renewal" reminder for this product.', 'your-textdomain' ),
    ) );

    woocommerce_wp_checkbox( array(
        'id'          => '_include_customer_notification_auto_renewal',
        'label'       => __( 'Auto Renewal reminder email', 'your-textdomain' ),
        'description' => __( 'Enable sending the "Auto Renewal" reminder for this product.', 'your-textdomain' ),
    ) );

    woocommerce_wp_checkbox( array(
        'id'          => '_include_customer_notification_subscription_expiration',
        'label'       => __( 'Subscription Expiration reminder email', 'your-textdomain' ),
        'description' => __( 'Enable sending the "Subscription Expiration" reminder for this product.', 'your-textdomain' ),
    ) );

    echo '</div>';
}

/**
 * Save the checkbox values when a simple subscription product is saved.
 */
add_action( 'woocommerce_process_product_meta_subscription', 'wcs_save_sub_reminders_fields_simple' );
function wcs_save_sub_reminders_fields_simple( $post_id ) {
    // Each checkbox either saves "yes" or "no".
    $fields = array(
        '_include_customer_notification_manual_trial_expiration',
        '_include_customer_notification_auto_trial_expiration',
        '_include_customer_notification_manual_renewal',
        '_include_customer_notification_auto_renewal',
        '_include_customer_notification_subscription_expiration',
    );

    foreach ( $fields as $field ) {
        $value = isset( $_POST[ $field ] ) ? 'yes' : 'no';
        update_post_meta( $post_id, $field, $value );
    }
}

/**
 * Show "Subscription Reminder" checkboxes for each variation
 * in a variable subscription product.
 */
add_action( 'woocommerce_product_after_variable_attributes', 'wcs_variation_subscription_reminders_fields', 10, 3 );
function wcs_variation_subscription_reminders_fields( $loop, $variation_data, $variation ) {

    // We'll create 5 checkboxes (auto/manual trial expiration, auto/manual renewal, subscription expiration).
    // Each checkbox is stored as meta on the variation itself.

    woocommerce_wp_checkbox( array(
        'id'          => "_include_customer_notification_manual_trial_expiration_{$variation->ID}",
        'label'       => __( 'Manual Trial Expiration Reminder', 'your-textdomain' ),
        'description' => __( 'Enable the "Manual Trial Expiration" reminder for this variation.', 'your-textdomain' ),
        'value'       => get_post_meta( $variation->ID, '_include_customer_notification_manual_trial_expiration', true ),
    ) );

    woocommerce_wp_checkbox( array(
        'id'          => "_include_customer_notification_auto_trial_expiration_{$variation->ID}",
        'label'       => __( 'Auto Trial Expiration Reminder', 'your-textdomain' ),
        'description' => __( 'Enable the "Auto Trial Expiration" reminder for this variation.', 'your-textdomain' ),
        'value'       => get_post_meta( $variation->ID, '_include_customer_notification_auto_trial_expiration', true ),
    ) );

    woocommerce_wp_checkbox( array(
        'id'          => "_include_customer_notification_manual_renewal_{$variation->ID}",
        'label'       => __( 'Manual Renewal Reminder', 'your-textdomain' ),
        'description' => __( 'Enable the "Manual Renewal" reminder for this variation.', 'your-textdomain' ),
        'value'       => get_post_meta( $variation->ID, '_include_customer_notification_manual_renewal', true ),
    ) );

    woocommerce_wp_checkbox( array(
        'id'          => "_include_customer_notification_auto_renewal_{$variation->ID}",
        'label'       => __( 'Auto Renewal Reminder', 'your-textdomain' ),
        'description' => __( 'Enable the "Auto Renewal" reminder for this variation.', 'your-textdomain' ),
        'value'       => get_post_meta( $variation->ID, '_include_customer_notification_auto_renewal', true ),
    ) );

    woocommerce_wp_checkbox( array(
        'id'          => "_include_customer_notification_subscription_expiration_{$variation->ID}",
        'label'       => __( 'Subscription Expiration Reminder', 'your-textdomain' ),
        'description' => __( 'Enable the "Subscription Expiration" reminder for this variation.', 'your-textdomain' ),
        'value'       => get_post_meta( $variation->ID, '_include_customer_notification_subscription_expiration', true ),
    ) );
}

/**
 * Save our "Subscription Reminders" checkboxes for each variation.
 */
add_action( 'woocommerce_save_product_variation', 'wcs_save_variation_subscription_reminders_fields', 10, 2 );
function wcs_save_variation_subscription_reminders_fields( $variation_id, $i ) {

    $fields = array(
        '_include_customer_notification_manual_trial_expiration',
        '_include_customer_notification_auto_trial_expiration',
        '_include_customer_notification_manual_renewal',
        '_include_customer_notification_auto_renewal',
        '_include_customer_notification_subscription_expiration',
    );

    foreach ( $fields as $field_key ) {
        // The input name in the HTML is the field name plus the variation ID,
        // e.g. "_include_customer_notification_auto_renewal_123"
        $field_name = $field_key . '_' . $variation_id;

        // If checkbox is checked, store "yes," otherwise "no."
        $value = isset( $_POST[ $field_name ] ) ? 'yes' : 'no';

        update_post_meta( $variation_id, $field_key, $value );
    }
}

/**
 * Helper: Determine if at least one item in the subscription has the given meta key set to "yes."
 *
 * @param  WC_Subscription $subscription
 * @param  string          $meta_key  e.g. '_include_customer_notification_auto_renewal'
 * @return bool            True if at least one product or variation has that meta = "yes."
 */
function wcs_subscription_has_enabled_meta( $subscription, $meta_key ) {
    foreach ( $subscription->get_items() as $item ) {
        $product = $item->get_product();
        if ( ! $product ) {
            continue;
        }

        // If this is a variation (from a variable subscription):
        if ( $product->is_type( 'variation' ) ) {
            // Variation-level meta
            $value = $product->get_meta( $meta_key );

        } else {
            // Simple subscription or some other product type:
            $value = $product->get_meta( $meta_key );
        }

        if ( 'yes' === $value ) {
            // Found at least one item that wants this email enabled.
            return true;
        }
    }
    return false;
}

/**
 * Auto Trial Expiration
 */
add_filter( 'woocommerce_email_enabled_customer_notification_auto_trial_expiration', 'wcs_limit_auto_trial_expiration_email', 10, 2 );
function wcs_limit_auto_trial_expiration_email( $enabled, $subscription ) {
    if ( ! $enabled || ! $subscription ) {
        return $enabled;
    }
    return wcs_subscription_has_enabled_meta( $subscription, '_include_customer_notification_auto_trial_expiration' );
}

/**
 * Manual Trial Expiration
 */
add_filter( 'woocommerce_email_enabled_customer_notification_manual_trial_expiration', 'wcs_limit_manual_trial_expiration_email', 10, 2 );
function wcs_limit_manual_trial_expiration_email( $enabled, $subscription ) {
    if ( ! $enabled || ! $subscription ) {
        return $enabled;
    }
    return wcs_subscription_has_enabled_meta( $subscription, '_include_customer_notification_manual_trial_expiration' );
}

/**
 * Auto Renewal
 */
add_filter( 'woocommerce_email_enabled_customer_notification_auto_renewal', 'wcs_limit_auto_renewal_email', 10, 2 );
function wcs_limit_auto_renewal_email( $enabled, $subscription ) {
    if ( ! $enabled || ! $subscription ) {
        return $enabled;
    }
    return wcs_subscription_has_enabled_meta( $subscription, '_include_customer_notification_auto_renewal' );
}

/**
 * Manual Renewal
 */
add_filter( 'woocommerce_email_enabled_customer_notification_manual_renewal', 'wcs_limit_manual_renewal_email', 10, 2 );
function wcs_limit_manual_renewal_email( $enabled, $subscription ) {
    if ( ! $enabled || ! $subscription ) {
        return $enabled;
    }
    return wcs_subscription_has_enabled_meta( $subscription, '_include_customer_notification_manual_renewal' );
}

/**
 * Subscription Expiration
 */
add_filter( 'woocommerce_email_enabled_customer_notification_subscription_expiration', 'wcs_limit_subscription_expiration_email', 10, 2 );
function wcs_limit_subscription_expiration_email( $enabled, $subscription ) {
    if ( ! $enabled || ! $subscription ) {
        return $enabled;
    }
    return wcs_subscription_has_enabled_meta( $subscription, '_include_customer_notification_subscription_expiration' );
}

Summary: Adds ability to enable woocommerce subscription reminders for only certain subscription products. First this feature must be enabled globally ( WooCommerce -> Settings -> Subscriptions (tab) ) and then each subscription product will show checkboxes to enable particular emails on a per product basis.

Simple Subscription: A custom “Subscription Reminders” tab in Product Data (only visible for type=subscription) for the parent product. The chosen checkboxes save as post meta (e.g. _include_customer_notification_auto_renewal = yes/no).

Variable Subscription: Each variation can be configured independently via five new checkboxes in the Variations panel. These also save as meta on the variation.

Email Filters: When a subscription triggers a reminder email, we check all items in the subscription. If any item (simple or variation) has the relevant meta set to yes, we allow that email. Otherwise, it’s disabled.