Let's separate two concepts:
- Upgrade the Ziti version you're deploying with Helm
- Upgrade the Chart version you're using to deploy Ziti with Helm
For any production environment, you'll benefit from having a test stage as close to it as practically possible so you can prove upgrade candidates.
You're asking about upgrading Ziti version 1.1.5 to 1.6.9. This is not a question of Helm Chart versions, but Ziti versions. You can review the differences in the Ziti CHANGELOG before overriding the Ziti version in your Ziti Controller Helm Chart Release like image.tag: 1.6.9.
After the Ziti Controller Helm Chart was released with default Ziti version 1.1.5, the Helm Chart major version was incremented to v2.0.0 due to a breaking change. To upgrade your chart version, you must perform the one-time migration procedure in the "Breaking Change" section of the controller deployment guide for Kubernetes: Install the Controller in Kubernetes | NetFoundry Documentation. The purpose of the breaking change is to break the dependency on Cert Manager and Trust Manager so they can be upgraded separately from Ziti Controller.
The Ziti Version
Each Helm Chart comes with a default Ziti version. You can upgrade the Ziti version by overriding the image.tag input value. As a rule, there's no reason you shouldn't override the Ziti version to upgrade or downgrade.
Upgrading Ziti may trigger a datastore migration. If this happens, it will not be possible to downgrade the Ziti version without first restoring a database with the same or lower datastore version required by the target Ziti version. Ziti automatically triggers a database snapshot before migration. The snapshot is stored in the same directory as the Bolt DB file in the controller's storage volume.
The Chart Version
Helm uses semver, and we follow suit, so you may use Helm version constraints to express your level of risk acceptance.
Examples:
--version='^2.0.0'means "upgrade unless major (breaking) revision", or--version='~2.0.0'means "upgrade unless minor (features added) revision".