Release 20161021 Summary of changes: CLOCK: An updated NuSTAR clock correction file, version 63, is available. This file is up to date through 2016-10-21, compared to 2016-09-22 in the previous version. Performance is OK (residuals mostly within < 2 sec, ~2 sigma, see attached plot). However there are three dates where residuals are poor due to spikes in the clock correction values: 2464 = 2016:274 = 2016-09-30 0000 hrs +/- 12 hrs (1) 2470.3 = 2016:280 = 2016-10-06 0715 hrs +/-12 hrs (2) 2477.7 = 2016:287 = 2016-10-13 1645 hrs +/- 12 hrs (3) 1) during 60201017002 (IC_2497), 80102101002 (GRS_1739m278) 2) during 60111034002 (UDS_MOS034), 60111035001 (UDS_MOS035) 3) during 60111039001 (UDS_MOS039), 60111040001 (UDS_MOS040) The clock file is available from the SOC public website: http://www.srl.caltech.edu/NuSTAR_Public/NuSTAROperationSite/clockfile.php