Frederik Denkens published this on 11 June 2024. The page was touched again on 18 March 2026. It first went out on the Skyscrapers changelog, which is how they tell customers about the reference platform.
Skyscrapers runs infrastructure as code on Terraform. From the end of May 2024 they were fully on OpenTofu 1.6.2. The trigger he names is the license change in Terraform 1.6.0 and later. He points at HashiCorp’s announcement that the license moved to the Business Source License. I got a 429 from that HashiCorp URL, so the license story here is his, not a fresh reading of HashiCorp’s post.
The Terraform → OpenTofu playbook is the state, provider, and plan work. This post is the rollout order inside a company that manages customer infrastructure. It is about 400 words.
Four phases
Terraform sits in the middle of how they manage infrastructure, so they wrote the cutover down as four phases.
The platform team tried OpenTofu as a drop-in replacement and checked compatibility.
Once those stacks were updated and tested, the whole Skyscrapers team moved over.
After more testing, they changed CI/CD so deployments and infrastructure changes ran OpenTofu.
They then told customers why, what to consider, and where the help docs were, in case a customer wanted to change their own infrastructure.
He does not say how many stacks, how long each phase took, or whether a plan showed a surprise diff. “Drop-in” is the compatibility claim. The post does not show a state file, a backend block, or a version pin.
What comes next in his note
With 1.6.2 done, the next step he names is OpenTofu 1.7.0. He links the OpenTofu site, the milestone list, the docs, and the registry.
OpenTofu’s migration page, as it stood when I read it, is a short overview. Back up state and code, install OpenTofu, init and verify, test a small change. It sends you to a longer guide, and it calls out terraform_remote_state between stacks. Skyscrapers does not say they followed those steps. If your estate shares state between configurations, that page is the warning their post leaves out.
What I would copy
Copy the order of people, not the missing commands. One team proves the binary. The rest of the company switches. CI changes after that. Customers hear it last, with a reason and a doc, because Skyscrapers changes infrastructure that customers run.
Keep a written version. “End of May 2024, OpenTofu 1.6.2” is the only fact a later audit can check. They do not publish the state procedure, so take the backup step from OpenTofu’s guide before you treat tofu as a rename of terraform.