Looker periodically deprecates certain product features. In some cases we provide a related "legacy feature" option, which allows you to continue using the deprecated feature while you implement a migration plan to improved functionality.
Looker brings you new features at a rapid pace. Sometimes we create a new feature, or make an improvement, that could be a breaking change and cause problems in your workflow.
To avoid such problems, we have the concept of Legacy Features – features that remain for backwards compatibility with your existing workflows. These legacy features eventually go away, but the legacy features enable you to upgrade Looker and then migrate away from the old functionality at your own pace.
Learning About Deprecations
Watch the release notes to be notified that we are deprecating a feature. You also can read this article for legacy feature end-of-life schedules, and information about how to transition away from deprecated features.
Enabling and Disabling Legacy Features
Admins have access to the Legacy Features panel, where features that have been phased out can be turned on and off. The list of features varies by release but looks like this:
When Looker is upgraded, any relevant legacy features are automatically turned on (checked). This means the old feature is still active. When you're ready to move to the new feature, you can turn the legacy feature off (un-checked).
If your company started using Looker after a feature was deprecated, that feature won't appear in the Legacy Feature panel and you won't be able to turn it on. This prevents you from accidentally using features we have deprecated. The Legacy Feature panel won't appear at all if there's nothing for you to configure.
Migrating Away from Legacy Features
Legacy features are features we plan on removing in future releases of Looker, so we strongly recommend moving away from their use. Legacy features can often be confusing or inconsistent, which is why they've been replaced with something we think works much better.
Start Planning Your Migration When a Feature Is Deprecated
We announce deprecations in the release notes. When Looker deprecates a feature, we provide information about what to do instead. You can also look at the full list of deprecations to help you plan your migration away from the deprecated features. That article also provides an end-of-life schedule, and information about how to transition away from the deprecated features.
You should expect that all legacy features will be turned off eventually. Thus, we recommend checking whether you are using the feature. If you are using it, leave the legacy feature enabled while you change your code. After you have completed the migration you can turn off the legacy feature.
Replacing a Legacy Feature
Almost all legacy features include some type of replacement functionality. Please reach out to support if you have any issues implementing the improved replacement feature.