LEAPSECONDS KERNEL VERSION NAIF0012 The file naif0012.tls is a unix-style text file. It is suitable for use on all unix boxes, including PC/linux and MAC/OSX machines. For PCs running Windows, use naif0012.tls.pc. Use of one of these files is required for all SPICE computations dealing with times on or after January 1, 2017 00:00:00 UTC if you want accurate conversions between UTC and Ephemeris Time (a.k.a. TDB). Failure to use naif0012 for times after this epoch will result in a one second time conversion error. The symbolic links latest_leapseconds.tls latest_leapseconds.tls.pc refer respectively to the files naif0012.tls naif0012.tls.pc These links are updated as necessary to point to the latest versions of the unix and windows leapseconds kernels.