This tax season I got an email from IRD reminding me I had to file my return. This happens every year and is usually not a surprise. However this year, the returns were slightly different. They said: The 31 March 2019 IIT return for {person} is due 8 July 2019. and The 31 March 2019 ITN return for {company} is due 8 July 2019. I’d never heard of an IIT return or an ITN return.