That 12 months is the minimum guaranteed period that your service won't be interrupted. See the full list of deprecations in App Engine: https://cloud.google.c

That 12 months is the minimum guaranteed period that your service won't be interrupted. See the full list of deprecations in App Engine: https://cloud.google.com/appengine/docs/deprecations/ https://cloud.google.com/appengine/docs/deprecations/ High profile deprecations are handled carefully and we usually handle them with extended deprecation period with clear migration path/doc and communications. Notable examples in the table: 1. Python 2.5: 4+ years 2. Java 6: 20 months with existing user automigrate to Java 7 3. Java 7: 13 months with existing user automigrate to Java 8 4. Master/slave datastore: 3+ years. Considering App Engine is the first Google Cloud offering, I'd say we have a very good track record of meet our deprecation policy and usually exceeds it.