I have a date in this format: "YYYY-MM-DD HH:MM:SS+HHMM" how can I convert it to UTC?
write $zdth("2018-02-01 00:00:00+0600",3,5)
As you see, timezone is lost. Docs for $zdth in timeopt (5) state: Specify time in the form "hh:mm:ss+/-hh:mm" (24-hour clock). The time is specified as local time. The following optional suffix may be supplied, but is ignored: a plus (+) or minus (–) suffix followed by the offset of local time from Coordinated Universal Time (UTC)