Upgrade Debian Jessie to Buster (10)

Hi Joe, thanks for the fast reply. Could you tell me which file do I need to update for repositories? Where is it located? Or is there an Update button on Virtualmin/Webmin GUI? I didnt see that. Also trying to update packages on Virtualmin GUI fails. Assuming I updated repository paths successfully, “sudo apt-get update && time sudo apt-get dist-upgrade” shall I continue to upgrade my dist with following command or is there a recommended/safe way over Virtualmin GUI? Like Upgrade Dist button? Thanks a lot!