Have a finicky legacy system you just can't seem to upgrade? Have you upgraded a tool just to watch it sink back into decay, despite your best intentions? We've been there, made it through to the other side, and want to share what we learned! Come learn about software rot, how to avoid it, how to reverse its effects, and what to do when you can't. This talk will include technical lessons (e.g., testing strategies, designing upgrade paths) and non-technical lessons (e.g., empathize with the people who wrote the code, understand the processes that lead to the current situation).