Microsoft Bot Framework SDK V4 was released in September 2018, and since then we have shipped a few dot-release improvements. As announced previously, the V3 SDK is being retired with final lifetime support ending on December 31st, 2019.
Accordingly, on July 1st, 2019 Microsoft will discontinue the ability to create new V3 Bots via Azure Portal or the CLI tool. Existing V3 bot workloads will continue to run without interruption. We have no plans to disrupt any running workloads.
We highly recommend that you start migrating your V3 bots to V4. In order to support this migration we have produced migration documentation and will provide extended support for migration initiatives (via standard channels such as Stack Overflow and Microsoft Customer Support).
For more information please refer to the following references: