"Please see here for the lates content about this dataset. LiDAR point cloud data for Washington, DC is available for anyone to use on Amazon S3. This dataset, managed by the Office of the Chief Technology Officer (OCTO), through the direction of the District of Columbia GIS program, contains tiled point cloud data for the entire District along with associated metadata."
The most recent data is from 2018 and 2015 data is available as well. A new data acquisition is planned for 2020.