If you're responsible for proper timekeeping you probably have already thought about the upcoming leap second at the end of Tuesday 2015-06-30 UTC. This is the first leap second in eighteen years that has fallen on a non-holiday weekday. It might not hurt to run through your checklist again, and (if you haven't already done so) compare it to the checklist recommended by GPS.GOV, NAVCEN, NCCIC, NIST, and USNO. You can find that checklist here: http://www.gps.gov/news/2015/05/leap-second/2015-best-practices-for-leap-sec... The new leap second has been in the tz database since release 2015a dated 2015-01-29 22:35:20 -0800, so if you're newer than that you should be good as far as tz is concerned. In the typical case where you're not using tz's leap-second support, you don't need to worry about tz at all.