You should get that from the PO. If you need it for work or for some other life requirement, the PO will be helpful.
If you want to know when you can do something you aren’t allowed to do on probation, you should rethink your actions.
And you should have all the paperwork from court. When you were ordered on probation, the form given to you by the court clerk will have the date when probation is over on it, Where is the paperwork?