[1] pry(main)> Time.strptime('<16.08.2017 13:35> <UTC+4>', '<%d.%m.%Y %H:%M> <UTC%z>').to_s(:iso8601)
=> "2017-08-16T13:35:00+06:00"
2.3.1 :002 > DateTime.strptime('<16.08.2017 13:35> <UTC+4>', '<%d.%m.%Y %H:%M> <UTC%z>').iso8601
=> "2017-08-16T13:35:00+04:00"