When a tenant breaks a lease, the landlord has an obligation to mitigate his losses and try to re-rent the unit as soon as possible.  As of September 1, 2021, landlords can file an application to collect rent arrears and/or compensation that you believe the former tenant owes you with the LTB within one year from the date the tenant moved 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.