Would it be possible to associate multiple instances of time_zone_base chained together with a local_date_time? I'm sure that the local_date_time object doesn't support this, but maybe it would be less hazardous than a change to time_zone_base? WRT the historical time zone change support, that's actually huge for me because without it I cannot use boost::date_time without it. I'm about to write my own wrapper for mining the zoneinfo DB for the POSIX string so that I can use boost::date_time. It seems like in the case of simple DST zones (where DST is either on or off), historical TZ changes could be incorporated with another init constructor that takes the "US/Eastern" type string argument and then goes and queries the TZ DB whenever the user uses the time_zone_base_ptr to construct a local_date_time object. I'll send code once I have it. -- View this message in context: http://boost.2283326.n4.nabble.com/date-time-Time-zone-improvements-tp265279... Sent from the Boost - Dev mailing list archive at Nabble.com.