utc+6 works fine.
But a time like "7 utc+6" will not be converted as the hour is ambiguous.
"7:00 utc+6" and "7am utc+6" will be treated as converting from 7am.
"19:00 utc+6" and "7pm utc+6" will be treated as converting from 7pm.
("19 utc+6" doesn't get converted, I should see to that)