What's New in CDK Terrain v0.23

CDK Terrain (CDKTN) v0.23.0 shipped on 2026-05-05, and four patch releases followed through v0.23.4 on 2026-07-02. v0.23.0 dropped support for end-of-life language runtimes. The patch releases added new features, so this page covers the whole 0.23.x line. To upgrade from v0.22, follow the v0.23 upgrade guide.

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Breaking changes

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Dropped language runtimes (v0.23.0)

v0.23.0 no longer supports Python 3.8, Go 1.18 to 1.24, or TypeScript versions below 4.5. The new minimums are Python 3.9 and Go 1.25. Generated provider bindings now use the TypeScript 4.5 type modifier on imports (see Generated TypeScript bindings). The v0.23 upgrade guide has the exact steps for each language.

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Features

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Mixins (v0.23.0)

v0.23.0 raised the constructs peer dependency to ^10.6.0, which brings the IMixin interface and the construct.with(...) method. You can apply reusable behavior to a single construct without subclassing. Learn more.

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Fail on constructs outside of stacks (v0.23.0)

The new failOnConstructsOutsideOfStacks feature flag makes synthesis fail when a construct is scoped directly to the App instead of a TerraformStack. Such constructs never appear in any stack’s output. cdktn init enables the flag for new projects. See Feature Flags.

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StringMapMap for nested map attributes (v0.23.0)

Some provider schemas define attributes as a map of string maps (map(map(string))). Provider generation previously failed on them. Generated bindings now expose these attributes as the new StringMapMap class, whose lookup(key) method returns a StringMap.

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Generated TypeScript bindings

• type modifier on imports (v0.23.0): generated provider and module bindings import types with import { ..., type X }. You can now compile projects that use generated bindings with isolatedModules, verbatimModuleSyntax, or preserveValueImports.
• Configurable import extensions (v0.23.2): set languageOptions.importExtension in cdktf.json to ".js" or ".ts", and cdktn get emits fully qualified relative imports (for example ./<folder>/index.js) for ESM toolchains. Without the setting, CDKTN keeps extensionless imports.
  {
    "language": "typescript",
    "languageOptions": {
      "importExtension": ".js"
    }
  }
  

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Faster synthesis (v0.23.3)

• CDKTN now serializes synthesized JSON with safe-stable-stringify instead of json-stable-stringify. In the benchmarks in cdk-terrain#224, this made serialization about twice as fast.
• Set the CDKTN_DISABLE_CREATION_STACK environment variable to true or 1 to skip capturing a stack trace for every token CDKTN creates. Capturing stack traces is slow in Node.js, so this speeds up synthesis of large stacks. The trade-off is that error messages no longer show where a token was created.

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Declared target versions (v0.23.4)

The new targetVersions field in cdktf.json declares the Terraform and OpenTofu versions your project supports. Synth-time validations check against this declaration without running a binary. The optional validateInstalledBinary setting checks the installed binary before diff, deploy, destroy, and output. v0.25 extended synth-time validation against targetVersions to moved blocks, import blocks, terraform_data, and the cloud backend. Learn more.

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Function availability validation (v0.23.4)

The Fn bindings now cover functions from current Terraform and OpenTofu releases. The validateFunctionVersions feature flag checks the functions you use against your targetVersions at synth time. The validation became the default in v0.24, and the flag was removed. Learn more.

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S3-native state locking (v0.23.4)

S3Backend gained a useLockfile field that locks state with a lock file in S3 instead of a DynamoDB table, and dynamodbTable is deprecated. Learn more.

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Deprecations

• S3Backend.dynamodbTable (v0.23.4): use useLockfile instead. See S3-native state locking.

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Notable fixes

• CLI (v0.23.4): interrupting cdktn diff or cdktn deploy releases the Terraform state lock. Terraform error output is no longer mistaken for a missing-variable prompt.
• Pre-built Java providers (v0.23.4): the CLI resolves pre-built Java provider versions via repo1.maven.org.
• Provider generation (v0.23.4): shorthand provider sources now match OpenTofu schema keys.
• Provider generation (v0.23.1): fixes code generation failures caused by provider names that collide when case is ignored.
• CLI (v0.23.0, v0.23.2): the CLI supports pre-built provider metadata with a cdktn key, and interactive input is no longer split between cdktn and Terraform.

See the CHANGELOG for the complete list.

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Pre-built providers

These changes landed in the pre-built provider packages (@cdktn/provider-*) while v0.23 was current:

• CDKTN 0.23 pin: the pre-built providers moved to cdktn ^0.23.0, constructs ^10.6.0, and jsii/TypeScript 5.9. This shipped as a new major version of each provider.
• New provider majors: Google and Google Beta moved to provider v7, Docker (kreuzwerker/docker) and Datadog to v4, and Kubernetes to v3. Each is a breaking change for code that uses those providers. Check the upstream provider’s upgrade notes before you bump.
• Node.js floor: pre-built provider packages declare engines.node >=22.11.0 instead of >=20.16.0, starting with each provider’s next major release.
• Publishing: Maven and NuGet publishing were re-enabled for the pre-built providers. npm and PyPI packages are now published with trusted publishing (OIDC).

Browse all pre-built providers and their current versions on the provider dashboard.