You can find the info you're after and read different experiences freelancers from Serbia shared on the Upwork supported "Freelancers in Serbia" Facebook group. Please follow this link.
You can also google for blogs in Serbian created by Upwork and Elance users, which do offer useful information about freelancing in Serbia.
For future reference, I think you'll get more replies from Upwork users in Serbia if you post related questions in the Serbia Country group here.
Thank you for your reply. My original post was in the group but I thought it would go unnoticed.
Thank you for the link to the Facebook group, I will try to find the information there.
I have just the right group for you, where you can find all the current information and answers to all of your questions, precisely from the users of Payoneer in Serbia, including me. You will have to request to join, but I can add you right away. Click this link - PayoneerSerbia.
I hope this helps! All the best!