The filing date of a return for a taxpayer who has died during the tax year is the latter of the normal filing date or 6 months after death occurred.
For instance, if a taxpayer passed away on January 20th 2020, the final return would still be due April 30th 2021.
While it is possible to prepare a final return within the year of death, this is considered an early-filed deceased return and there is no CRA requirement that it be done.
A final return is the return completed in the year of death. The final return and all prior years must be filed.
If the taxpayer died after the tax year end, the return is a normal return. Only the return for the year of death is a final return. It is called a final return because no T1 returns can be completed for tax years after the year of death.