In August 2016, reprocessing began for Landsat 4-5 (L4-5) Thematic Mapper (TM) and Landsat 7 (L7) Enhanced Thematic Mapper Plus (ETM+) scenes. Data initially became available in September 2016 and finished Collection 1 processing in February 2017.
In February 2017, reprocessing began for Landsat 8 (L8) Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS) scenes. Data initially became available in March 2017 and Collection 1 processing is expected to last until June 2017.
Landsat 1-5 Multispectral Scanner (MSS) data will be considered after the TM, ETM+, and OLI/TIRS reprocessing efforts have completed.
Each reprocessing effort will begin with the most recently acquired data and will move backwards into the archive. The conterminous United States will be processed first, followed by international areas.
The Landsat Collections Web page contains the details about all aspects of the Collection 1 effort.