If you need a Serbian visa, please apply for it in a good time - see http://www.mfa.gov.rs.
TELFOR organizers can send a typical invitation letter to you. Each author of an accepted paper can request invitation letter. To request invitation letter, please, Sign in to the online registration and submission system. After that, follow the link 'Request for visa invitation letter ' on the left side menu (My Papers submenu).
Unfortunately, in some cases the TELFOR invitation letter is not enough to get the Serbian visa. Different Serbian embassies or other diplomatic missions have different requests and procedures, depending on the country from which the visa applicant is coming from. We advise you to check with the Serbian diplomatic mission where you intend to apply for the Serbian visa what are the specific requests (if any) and what kind of invitation letter or other document they expect. You can find the list of Serbian diplomatic missions at http://www.mfa.gov.rs. Please inform us as soon as possible firstname.lastname@example.org.