On December 19 the TIRS instrument on Landsat 8 was reconfigured due to detection of anomalous current levels associated with the scene select mirror encoder electronics. Since that time substantial testing has been conducted to isolate the root cause of the problem and to evaluate options for returning to routine operations.
During this time, TIRS data has been routinely collected with OLI data, but due to the lack of definitive calibration coefficients the processing of TIRS data to level-1 products has been suspended.
Once a plan to return to normal operations has been defined, the backlog of TIRS data that have been collected will be processed to Level-1 products. Updates to the status of plans to resume normal operations will be provided periodically.
Visit the USGS Landsat website for the latest details.

Above the Earth, Below the Surface: Landsat’s Role in Monitoring Water Quality
Safeguarding freshwater resources is crucial, and while scientists use a variety of ground-based techniques to gauge water quality, the Landsat program has provided water quality data from orbit for decades.