Currently, the link for guest orders is only valid for 30 days. This value is hard-coded in the source code in such a way that it cannot be easily overwritten with a simple event listener. It is necessary to decorate the entire OrderRoute and completely override the load() method in order to adjust the value within the filterOldOrders() method, which is unfortunately private.

The value of 30 days is often far too short, especially when the shop works a lot with pre-orders that can be ordered months in advance. The support effort for this is immense.

At the moment, the only option is to use the plugin from Acris: https://store.shopware.com/de/acris66565174266m/bestellbestaetigung-link-in-e-mail-funktioniert-nach-30-tagen-nicht-mehr-jetzt-einstellbar.html

The adjustments required for this compromise update security and make the entire system unnecessarily complicated, even though it would be easy to add a setting for this in the core.