On Monday, November 30, 2020, in accordance with the 
deprecation schedule, v201911 of the Ad Manager API will sunset. At that time, any requests made to this version will return errors.
If you’re still using v201911, now is the time to upgrade to a newer release and take advantage of additional functionality. For example, 
in v202002 we added a number of video and reporting features.
When you’re ready to upgrade, check the full 
release notes to identify any breaking changes, like 
Activity and 
ActivityGroup IDs 
changing from type int to type long in v202005. Then, grab the latest version of your client library and update your code. 
As always, don't hesitate to reach out to us on 
the developer forum with any questions.