The Sentry team is making changes to increase the reliability of sentry.io by updating its IP addresses, which may require customer-side updates to firewall rules for uninterrupted service. The new IP addresses will be used starting on June 21, 2017, and customers with existing network rules will need to update them to include these new addresses to ensure continued functionality. To alleviate the pains caused by this change, Sentry provides an alternative authentication method using a token that can be appended to outbound requests, allowing for more flexibility in security settings.