On Dec 11, 2018, Google did a live stream about the Google Ads API: Roadmap and migration webinar. The webinar had a duration of 1 hour and 1ß minutes and it was recorded. Watch here:
The slides are available here.
Google confirmed in the webinar that Adwords API will sunset approximately one year after Google Ads API v1, and Adwords API and Google Ads API will co-exist in 2019. Google says existing and new development should plan to use the Google Ads API.