You must upgrade your applications to thelatest supported runtime version to continue receiving security updates and be eligible fortechnical support.

The process of upgrading an existing app depends on the runtime version thatyour app currently uses:

• Go 1.11 (first-generation runtime): You must migrate your app to thelatest supported Go version. Go 1.11 has reachedend of support on January 30, 2024. Yourexisting Go 1.11 applications will continue to run and receive traffic. However,App Engine might block re-deployment of applications that use runtimesafter their end of support date.To migrate to the latest supported version of Go, seeMigrate from Go 1.11 to the latest Go runtime.

• Go second-generation runtimes (after end of support): To upgrade to asupported version of Go,update theapp.yaml file by specifying a version of Go that youwant your app to run. For example:

  runtime:goVERSION

  WhereVERSION is the GoMAJOR andMINOR version numbers.For example, to use the latest Go version, Go 1.25,specify125.For more information, see theGo runtime overview.