The App Engine flexible environmentruntimes use open source componentsthat are maintained by their respective communities. The runtimes areidentified by their language version, for example, Java 17, Python 3.10, and so forth.

Google provides support for a runtime duringGeneral availability (GA). During this support window:

• Runtime components are regularly updated with security and bug fixes.
• To maintain stability, App Engine avoids implementing breaking featuresor changes into the runtime. Breaking changes will be announced in advanceon the runtime-specificrelease notes.

When a language version is no longer actively maintained by the respective community,App Engine will also stop providing maintenance and support for that language runtime.Before a runtime reaches the end of support phase as described in theruntimes support schedule, Google will provide a notification to customers.

Google may make changes to any runtime's support schedule or lifecycle in accordance with the terms of your agreement for the use of Google Cloud platform services.

Custom runtimes

Custom runtimesallow you to define new runtime environments which may include additional componentslike language interpreters or application servers.

Custom runtimes are not impacted by the runtime lifecycle policy.

Runtime lifecycle

	GA-level support	End of Support	Deprecated	Decommissioned
Creation & redeployment	Yes	No	No	No
Project Configuration Updates	Yes	Yes	No	No
Running existing workloads	Yes	Yes	Yes	No
UI & CLI Warnings	Yes	Yes	No	No
Language patches	Automatic	No automatic updates	No automatic updates	No automatic updates
Patching APIs & SDKs	Automatic	No automatic updates	No automatic updates	No automatic updates
Customer Support	GA-level support	No runtime support	No runtime support	No runtime support

Notification period

App Engine will begin issuing in-app notifications 90 days before the applicationreaches end of support. Upon notification, you should prepare to upgrade your application to a newerruntime that is supported in the flexible environment.

End of support

Important: Google will no longer apply security updates or patches tocomponents of the runtime environment that have reached end of support. To continue receiving security updates, westrongly encourage you to upgrade your application to a supported runtimeversion as soon as it becomes available.

When runtime components reach the end of support date:

• Google will no longer apply security updates or patches to components of the runtime environment.
• Your application will continue to run and receive traffic.
• You will no longer be able to create and/or update the application on the unsupported runtime.
• Issues arising from the use of an unsupported runtime will not be eligible for technical support

We strongly encourage you to upgrade your application to a supported runtime version as soon as it becomes available to continue receiving security updates and being eligible for technical support.

Alternatively,you can redeploy your application using acustom runtime.

Deprecated

If Google allowed your Organization to re-enable deployments in an unsupported runtime, Google will remove that ability once the runtime is deprecated.

Where practicable, we will make reasonable efforts to notify you in advance of the deprecation by in-app notifications or other means. In certain instances, including in circumstances involving critical security vulnerabilities or similar high severity issues, advance notice may not be practicable.

Decommissioned

Applications that continue to use a decommissioned runtime may be disabled without further notice. You must choose a more up-to-date runtime to deploy your application.

See the runtimessupport schedule for key dates.