To updated the timezone files: 1- get the vzic tool from https://github.com/libical/vzic 2- update the Makefile PRODUCT_ID = -//Inverse inc.//NONSGML IANA 2016h//EN TZID_PREFIX = 3- get the zone files, for example: mkdir /tmp/zones cd /tmp/zones wget http://www.iana.org/time-zones/repository/releases/tzdata2016h.tar.gz tar -zxvf tzdata2016h.tar.gz 4- compile and run the conversion tool make -B ./vzic --olson-dir /tmp/zones --output-dir ../SOGo/SOPE/NGCards/TimeZones/ 5- cleanup cd ../SOGo/SOPE/NGCards/TimeZones/ rm -f zones.h zones.tab