WooCommerce Subscriptions 6.9.0

* Tweak: Delete Subscriptions transients when using the "Clear Transients" tool via the WooCommerce > System Status > Tools administration screen. (PR#1758)
* Tweak: Avoid infinite loops with old versions of the Shipping Multiple Addresses extension and potentially other extension that may manually instantiate the WC_Checkout object, which is normally a singleton accessed via WC()->checkout, WC()->checkout or WC_Checkout::instance(). (PR#1757)
* Tweak: When a subscription's date or status is updated, unschedule all corresponding scheduled actions, not just the first to ensure duplicate scheduled actions that may have been added by 3rd party code or manually are also unscheduled. (PR#1764)
* Fix: Do not require timestamps to be an integer in some date functions to fix issues where a string representation of a timestamp is used. Fixes issues with PayPal Standard Checkout & compatibility with the Groups for WooCommerce extension. (PR#1763)

* New: Subscription Reports to get insights into the performance of your subscription business: Subscription Reports - WooCommerce Docs
* New: Failed Recurring Payment Retry System to help recover revenue that would otherwise be lost: Failed Recurring Payment Retry System - WooCommerce Docs
* New: More subscription emails to help you keep on top of important events, like customer suspension and expiration: What’s New in Subscriptions 2.1 - WooCommerce Docs
* New: Cancellation date to keep track of when customers cancel subscriptions, not just when they end after being cancelled: What’s New in Subscriptions 2.1 - WooCommerce Docs
* New: Allow resubscribing to subscriptions Pending Cancellation: What’s New in Subscriptions 2.1 - WooCommerce Docs
* New: REST API Endpoints for Subscriptions built on WordPress REST API infrastructure: What’s New in Subscriptions 2.1 - WooCommerce Docs
* New: Additional order type filters on the WooCommerce > Orders administration screen to filter orders to show only subscription parent, renewal, resubscribe or switch orders: What’s New in Subscriptions 2.1 - WooCommerce Docs
* Tweak: Always use Renewal Order totals and data for renewal payments, making it possible to easily add one-time fees or discounts to renewals: What’s New in Subscriptions 2.1 - WooCommerce Docs
* Tweak: Improved responsiveness and layout of the subscription pricing fields on the Edit Product screen: What’s New in Subscriptions 2.1 - WooCommerce Docs
* Tweak: Use renewal order/subscription addresses as the default address fields loaded on checkout for renewal, resubscribe and switch checkouts. What’s New in Subscriptions 2.1 - WooCommerce Docs
* Tweak: Process switches (upgrades and downgrades) on order status change instead of when the customer completes checkout: What’s New in Subscriptions 2.1 - WooCommerce Docs
* Tweak: Small performance improvements by no longer calling deprecated hooks and caching some queries: What’s New in Subscriptions 2.1 - WooCommerce Docs
* Tweak: Apply add-to-cart validation to renewals and resubscribes (using the 'woocommerce_add_to_cart_validation' hook): What’s New in Subscriptions 2.1 - WooCommerce Docs
* Tweak: Link to the My Account > Subscriptions page on the Order Received/Thank you page when using WooCommerce 2.6 so that the customer can see all their subscriptions if they purchased multiple subscriptions in the transaction.
* Tweak: Use the 'pay_for_order' user capability check to determine whether a user can pay for a renewal and resubscribe rather than checking their ID against the customer ID on the subscription. (PR#1692 / PR#1716)
* Tweak: Increase next payment date threshold for end date to safeguard against payments being processed on the last day of a subscription. (PR#1689)
* Tweak: Only check for PayPal Reference Transaction support once per week instead of daily.
* Tweak: Consistently use the same tooltips in the store admin area as WooCommerce.
* Tweak: Initiate auto-switch process when loading the Grouped product page. (PR#1641)
* Tweak: New 'woocommerce_subscriptions_after_recurring_shipping_rates' hook.
* Tweak: Update scheduling system (Action Scheduler) to version 1.5.
* Fix: Do not create new orders when processing a renewal and resubscribe payment with different details to the original order by ensuring the cart hash used by WooCommerce is updated when creating the order. (PR#1687)
* Fix: Prevent My Account > Subscriptions endpoint page title overriding custom menus and other items on the page calling 'the_title' filter. (PR#1737)
* Fix: Do not change the status of subscriptions using PayPal Standard when the request to update the status at PayPal.com fails because of incorrect API credentials. (PR#1743)
* Fix: Display incorrect PayPal API credentials notice after a status change request or reference transaction check returns incorrect credentials error. (PR#1743)
* Fix: Calculate switching next payment date calculations for a free product to a non-free product correctly. (PR#1661)
* Fix: Process renewals with PayPal Reference Transactions correctly when the ALTERNATE_WP_CRON constant is defined. (PR#1733)
* Fix: Prevent grouped subscription products being switched to non-subscription product in the same grouped product. (PR#1666)
* Fix: Treat empty subscription suspension count option value as 0, meaning no suspensions are allowed. (PR#1728)
* Fix: Only attempt to get paid renewal orders if there are renewal orders. (PR#1718)