Form T1244 is the election that lets an individual defer paying the departure tax that arises when they cease to be a Canadian tax resident. On emigration, the deemed-disposition rules in section 128.1 treat most property as sold at fair market value, which can create tax on accrued gains even though nothing has actually been sold.
By filing the election, the departing taxpayer can defer paying the tax on the deemed disposition until the property is actually sold, rather than paying in the year of departure. Acceptable security must be posted with the Canada Revenue Agency for amounts above a threshold, although a portion can be deferred without security. The election manages the cash-flow problem created by a tax liability that arises without a sale, and it is generally addressed as part of pre-departure planning.