On Friday, August 30, 2019, in accordance with the 
deprecation schedule, v201808 of the Ad Manager API will be sunset. At that time, any requests made to this version will return errors.
If you’re still using this version, now is the time to upgrade to the latest release and take advantage of new functionality like 
DateTimeRangeTargeting, the 
TargetingPresetService, and 
reporting on CustomTargetingKeys.
When you’re ready to upgrade, check the 
release notes to identify any breaking changes. Significant changes include:
- A change to the capitalization of DateTime.timeZoneId, which was previouslyDateTime.timeZoneID.
- Removal of the ContentMetadataKeyHierarchyService. You can continue to target video content with key‑values mapped from content metadata or content bundles.
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.