We regularly update stacks by releasing new versions, such updates can include security updates and performance improvements. You can find more details under the Changelog tab on a stack page.
Stacks and infrastructure maintained separately
For infrastructure maintenance see this article
The stack has a requirement for the minimal version of infrastructure of the server where this stack is deployed. You can find a stack's version of your application on the list of your apps or under Stack tab of your instance. If a stack is outdated you will see an appropriate indicator.
Updating organization stack¶
When a new version of a stack has been released your stack will be marked as outdated. You can update a stack to the latest version from a stack page in your organization. This update will not affect your applications, it only updates the version of a stack inside of your organization.
Upgrading application stack¶
Once you update a stack in your organization, you can upgrade the application instances. Go the Instance > Stack > Operations page and click Upgrade . The downtime depends on the number of services affected in a new version and what deployment strategy used in these services.