The Unidata THREDDS Development Team released updated versions of the THREDDS Data Server (TDS) and netCDF-Java/Common Data Model (CDM) library on June 17, 2020. In addition to feature enhancements, these releases contain a variety of updates to third-party libraries, including security updates. They also address a problem in previous versions that could lead to data returned by some NetcdfSubsetService (NCSS) requests being corrupted. While the circumstances under which the problem occurs are very specific (and rare), because the possibility of data corruption exists the development team strongly recommends these upgrades to anyone using netCDF-Java/CDM or TDS. TDS administrators who are not able to upgrade immediately should disable the NetcdfSubsetService until it is possible to do so.