Valid definition of UTC offset is text using format "(+|-)hh[:mi[:ss]]", wherehhdefines the number of hours,midefines the number of minutes, andssdefines the number of seconds.
Sign
The sign, as well as the number of hours, are
mandatory
essential parts of offset definition, number of minutes and seconds are optional and default to 0 (e.g. "+02:30" defines offset of 2 hours and 30 minutes from UTC).