I received the yearly RTMT alert that the DST rules file for the current year is created by cron. I looked into this and found that to make sure the phones get the right time after Daylight Savings time, you need to reboot the phones after the DST rules file is created. In the US, Daylight savings is the same weekend this year as last. It is really necessary to reboot the phones? That is a pain in a 24/7 environment. We are running CUCM 10.5.