When our customers complete an upgrade, from WP Simple Pay Personal ($99) to Plus ($199), for example, they are charged a cost-based proration. This means that regardless of when the upgrade is performed, the customer will be charged the price difference between the current level and the level they are upgrading to. In the example above, this means the customer will pay $100.
The original renewal and license key date will remain unchanged. The date DOES NOT change to become the date the customer upgraded. Some customers may become confused by this, mainly if their renewal date closely follows the date they upgraded.
The information below can be used to explain and provide an answer when our customers ask about this.
When you initially purchased WP Simple Pay, an automatically renewing subscription was created for you. This subscription automatically renews every year on the initial purchase date and is tied to your license key date. When you upgrade your license, this is processed as a new charge and has no effect on your renewal date, which remains the same — the date of initial purchase.
Example: You purchased a Personal license for $99 on October 1, 2021. On March 1, 2022, you decide to upgrade your license to the Plus license, which is $199. You will pay $100 to upgrade. On October 1, 2022, your subscription will renew, and you will pay $199 and have an active license key until October 1, 2023.
Documentation: https://wpsimplepay.com/doc/upgrading-wp-simple-pay-pro-license/