If the tenant has moved out without paying the rent, as of September 1, 2021 section 87 (1.1) of the Residential Tenancies Act came into effect, landlords can file an arrears application with the LTB within one year from the date the tenant moves out of the rental unit.  The tenant must have moved out of the rental unit on or after September 1, 2021. However, in order to file this application with the LTB, you will have to find out their new residential address to be able to serve them. The prescribed form is available on the LTB website at http://tribunalsontario.ca/ltb/forms/.