# V1 build system deprecation (/docs/migration/v1-build-deprecation)

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Related: [SDK v2 migration guide](/docs/migration/v2.md), [V2 build system migration](/docs/migration/template-v2.md), [E2B_ACCESS_TOKEN deprecation](/docs/migration/access-token-deprecation.md), [How do I increase my concurrency limit?](/docs/faq/increase-concurrency.md)

The V1 build system is deprecated, and V2 is now the supported build system. V1 builds stop working on **August 1, 2026**, when [access tokens stop working](/docs/migration/access-token-deprecation) (V1 builds authenticate with `E2B_ACCESS_TOKEN`). Migrate to V2 before then to keep building.

## What changed [#what-changed]

The `e2b template build` command that drove V1 builds is now a deprecation stub and exits immediately. The current build command is `e2b template create`, which authenticates with your `E2B_API_KEY` instead of the access token. Migrating to V2 is therefore also what keeps your builds working past the access token cutoff.

## How to migrate [#how-to-migrate]

Follow the [V2 migration guide](/docs/migration/template-v2) to move an existing template to the V2 build system. It covers three paths:

* `e2b template migrate` to convert an existing `e2b.toml` and `e2b.Dockerfile` definition (recommended).
* `fromDockerfile()` to keep using a Dockerfile, parsed into a V2 template.
* `fromImage()` to reference a Docker image you build and push yourself.