Tenant won’t pay last month, already moved out

[Tony Borman]

Need some advice -

Rental property in Madison WI, lease August 2019 to August 2020. Tenant lost employment and informed me of difficulty paying rent starting in March. He offered to move out to a smaller/cheaper place he could afford if/as soon as I could find a new renter. Given the typically August to August lease cycle in Madison and the pandemic, I was not able to get the rental filled with a new tenant until August. Tenant moved out to more affordable rental at end of May and we agreed I would keep all security deposit to cover June rent and would discount July by $500 (of $1800). Tenant now confirms they will not be paying anything towards July. Anything I can do? Is it worth small claims?