Clients, married couple, both green card holders and not US citizens, voluntarily gave up their green cards on 6/20/18, after which they departed for their home country with no intention of returning to the US. Filed MFJ 1040 for 2017. Based on substantial presence test formula, total number of days for past 3 years= 189. In 2018=106 days; 2017= 67 days (200/3); 2016= 16 (97/6). Number of days in US in 2019 = zero.  What are their filing status for 2018? Full-year MFJ as resident 1040 based on substantial presence test? Or dual-status based on green card test by filing resident MFJ 1040 for period up to 6/20/18 and MFS 1040NR for period after 6/20/18 to year end?