The purpose of these updates
Version 3 of the Stripe system will allow your site to continue to qualify for the SAQ-A PCI DSS Compliance, where all you need to do is to confirm that all pages where you collect Credit Card Details are loaded securely using HTTPS.
Once you have done that, Stripe will be able to automatically fill out your PCI DSS Assessment Questionnaire without any further input from the site owner.
The update to your site should be seamless - there is nothing you have to do, and the new system will simply replace the old integration on your Subscription Forms, Account Update page and in the Control Panel.
If your PCI Compliance documentation at Stripe has recently expired, it may detect that you are currently using the old integration, and tell you that you need to fill out the more involved PCI Compliance assessment.
Once the update is applied, Stripe will automatically detect the update to Version 3 (usually takes between 2 days to a week, depending on the frequency of transactions being submitted from the site), and will restore your ability to fill out the SAQ-A assessment.
We will begin to roll out this update this week, as part of the same update to allow sites to prepare for the new GDPR regulations.