Graceful upgrades allow for the seamless replacement of a process's configuration and code without disruption, a necessity in environments lacking load balancing layers, such as Cloudflare. This process involves complex systems programming, with solutions like using the Go library tableflip, which Cloudflare plans to open-source. Graceful upgrades ensure that neither the listening socket is removed nor connections are dropped during code updates. Traditional methods like the Exec() function or using the SO_REUSEPORT flag have limitations, such as the inability to reverse the Exec() call or the risk of orphaned connections with separate sockets. Instead, models like NGINX's, which utilize a process-per-core approach along with a primary process to manage socket sharing during upgrades, offer a robust solution. This method ensures that only one upgrade is active, the new process can safely crash during initialization, and no old code persists post-upgrade. Despite existing libraries like tablecloth, beego/grace, and facebookgo/grace, none fully met Cloudflare's requirements for flexibility beyond HTTP protocols, prompting the creation of their library, tableflip, which facilitates NGINX-style upgrades in Go applications.