The Terraform license in short

Terraform has been under the Business Source License (BSL) 1.1 since 10 August 2023, and OpenTofu is the MPL 2.0 fork run by the Linux Foundation. Which one a team should use is partly a legal question, so AceMQ gives no license advice, and partly a technical one that a platform team can answer by trial. This article lists the dated facts, what is documented about compatibility, and five steps to decide. For upgrades, state work or an OpenTofu trial, see AceMQ's Terraform and OpenTofu support for platform teams.

• 10 August 2023: HashiCorp announced that all future releases of its products move from MPL 2.0 to BSL 1.1. Its announcement says APIs, SDKs and almost all other libraries stay MPL 2.0, and describes the permitted use as allowed "except where providing a competitive offering to HashiCorp".
• 20 September 2023: the Linux Foundation announced OpenTofu, previously OpenTF, as an open source alternative to Terraform.
• 27 February 2025: IBM completed its acquisition of HashiCorp.
• 4 November 2026: Terraform 1.17.1 (28 October) is the latest release. OpenTofu 1.13.2 (21 October) is the latest, and the 1.12 line is still patched, with 1.12.11 published on 29 October.

The BSL's additional use grant and its change date are in the license text itself. AceMQ has not summarized them here: a consultancy's summary is no substitute for your counsel reading the license.

OpenTofu says it aims to keep compatibility with Terraform configurations and that most Terraform code works without modification. Its migration guide names no Terraform versions and makes no formal statement about state compatibility. It does say that the first apply updates the state file format if needed, which is why the guide starts with a backup. Asked on its home page whether it will be compatible with future Terraform releases, OpenTofu answers only that the community will decide its features.

HashiCorp publishes an upgrade guide for each minor release from 1.1 to 1.17, and v1 compatibility promises for valid configurations. They cover the configuration language (apart from terraform.workspace), the protected CLI commands and flags (init, validate, plan, apply, show, output, fmt), JSON output and exit codes, and provider protocol 5. They exclude providers, external modules and experimental features, offer no stable state-file-format promise and do not guarantee downgrades.

1. Put the license question to counsel with your real use cases. List how Terraform is used: internal infrastructure, work for clients, anything embedded in a product you sell. The answer depends on the license text and those facts.
2. Inventory what you run. Terraform versions per pipeline, providers and their version constraints, backends, any use of HCP Terraform, and modules nobody owns.
3. Trial OpenTofu on one low-risk stack, in a copy. Back up the state, run tofu init, then tofu plan, which should show no changes or the same output Terraform gives. Apply once, then make a small change. Stacks that read each other through terraform_remote_state need extra care.
4. Write the revert path before you start. The guide's route is to restore the backups, then run terraform init and terraform plan and confirm nothing unexpected appears.
5. Decide per estate, not per company. Some stacks may move and others stay. Either way, pin providers with required_providers constraints, commit the lock file and keep one tool version across the pipelines that share state.

The decision costs most where Terraform or OpenTofu manages the nodes and volumes under a database or message broker. Terraform reads a changed resource address as a destroy and a create unless a moved block says otherwise, and HashiCorp's refactoring page requires Terraform 1.1 or later for moved blocks on module addresses. So read every plan that touches stateful resources, add prevent_destroy lifecycle rules, and do not auto-approve changes to anything that holds data. The same applies to OpenTofu. The RabbitMQ, Apache Kafka and Kubernetes pages describe the platforms AceMQ runs on top of this infrastructure.

If counsel is comfortable with the license for your use and nothing else pushes you to change tools, the work is upgrade discipline: read the upgrade guide for each minor on the path, rehearse with plan-only runs on a copy, and remember that providers and external modules sit outside HashiCorp's v1 promises. If counsel is not comfortable, or you want an MPL 2.0 tool under a foundation, a trial turns the technical half of the question into facts.

A trial does not answer the license question, and it cannot show how the two tools will diverge, because OpenTofu's community decides its own features. Set a review date, record which stacks ran unchanged, and revisit the decision when either project ships a release that changes how your providers or state behave.

• HashiCorp: HashiCorp adopts Business Source License, 10 August 2023, checked 4 November 2026
• IBM: IBM completes acquisition of HashiCorp, 27 February 2025
• Linux Foundation: Announcing OpenTofu, 20 September 2023
• OpenTofu: migration guide and opentofu.org, checked 4 November 2026
• Terraform v1.x compatibility promises, upgrade guides and refactoring modules, checked 4 November 2026
• Terraform releases and OpenTofu releases, checked 4 November 2026