See [code changes](https://github.com/coreos/etcd/compare/v3.3.0...v4.0.0) and [v4.0 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_4_0.md) for any breaking changes. **Again, before running upgrades from any previous release, please make sure to read change logs below and [v4.0 upgrade guide](https://github.com/coreos/etcd/blob/master/Documentation/upgrades/upgrade_4_0.md).**
-`clientv3.Client.KeepAlive(ctx context.Context, id LeaseID) (<-chan *LeaseKeepAliveResponse, error)` is now [`clientv4.Client.KeepAlive(ctx context.Context, id LeaseID) <-chan *LeaseKeepAliveResponse`](TODO).
- Similar to `Watch`, [`KeepAlive` does not return errors](https://github.com/coreos/etcd/issues/7488).
- If there's an unknown server error, kill all open channels and create a new stream on the next `KeepAlive` call.