Terraform is a popular Infrastructure-as-Code (IaC) tool for managing cloud environments, but its providers evolve rapidly, introducing frequent breaking changes. These updates pose migration challenges due to fragmented documentation and limited support, leading to delayed upgrades and accumulated technical debt. We present \textbf{TerraMod}, a framework that automates Terraform code migration across provider versions. It leverages external sources — changelogs, API schemas, and deprecation links to construct a migration context that guides LLMs towards effective upgrades. Evaluated on real-world breaking changes from the AWS Provider, \textbf{TerraMod} outperforms standard prompting techniques, enabling reliable upgrades. The dataset will be released upon publication.