Why Is a Plugin Update Breaking WooCommerce Subscriptions?

Why This Happens

Subscription renewals, switching, and payment processing all run through the same core WooCommerce checkout and order pipeline that every other checkout-related plugin also hooks into. A plugin update that changes hook priorities, adds new validation, or alters how it processes an order can interrupt that pipeline for subscription orders specifically, even if the plugin's own feature seems unrelated to subscriptions at all.

Common Causes

• Fraud-prevention or security plugins. These often intercept and can outright block orders matching certain patterns, and a renewal order (created without the customer actively at checkout) can trigger false positives that a normal order wouldn't.
• Caching plugins caching a logged-in customer's account or checkout pages. Serving a cached page during a payment-method change or checkout step can cause a customer to submit against stale data.
• Custom checkout field plugins. An update that makes a custom field newly required can silently block the automated renewal order-creation process, which doesn't go through the same checkout form a human fills in.
• Payment gateway plugin updates changing their own hook behavior or API version, breaking compatibility with how WooCommerce Subscriptions expects to interact with them.
• Two plugins both hooking into the same action with conflicting priorities after one of them updates and changes its own priority value.

How to Fix It

1. Reproduce the problem on a staging copy first — never debug a live payment or checkout issue by deactivating plugins on the production store.
2. Deactivate plugins one at a time, starting with anything updated recently or anything that touches checkout, fraud screening or payment processing, re-testing after each one.
3. Check the site's PHP error log for fatal errors or warnings timestamped around a failed renewal or checkout attempt — this often names the conflicting plugin directly.
4. Enable WooCommerce → Status → Logs for both WooCommerce core and the payment gateway in use, which frequently records more detail than what's shown in the admin UI.
5. Once isolated, check the plugin's own changelog for the version that introduced the problem — a genuine bug is often already reported, and a fix or workaround may already exist.

A conflict like this is usually quick to isolate but can be tedious to fix properly without breaking the other plugin's actual purpose — see WooCommerce fixes for a proper diagnosis rather than deactivating something you still need.