ST-2026-093 · SDKs, clients & toolchains
AWS SDK for JavaScript v3 introduces a rolling TypeScript support floor
From 4 January 2027, AWS SDK for JavaScript v3 supports TypeScript compiler versions released within the previous 2.5 years; TypeScript 5.5 and earlier are outside support at the first boundary.
Previous state
Before 4 January 2027, AWS SDK for JavaScript v3 had not yet applied the announced rolling policy that limits supported TypeScript compiler versions to a recent release window.
Current state
Starting 4 January 2027, AWS SDK for JavaScript v3 supports TypeScript versions released within the previous 2.5 years, using the DefinitelyTyped support window plus a six-month grace period. TypeScript 5.5 and earlier are outside support at that first boundary.
Affected users
Who needs to care
TypeScript projects that use AWS SDK for JavaScript v3 and remain on compiler versions that fall outside the rolling support window, beginning with TypeScript 5.5 and earlier on 4 January 2027.
Required response
What to do
Inventory the TypeScript compiler used by each SDK v3 project and upgrade to a supported version before its boundary, then run the project type check and address new diagnostics. If an immediate compiler upgrade is not possible, pin @aws-sdk/* packages to the last compatible release while accepting that newer SDK updates, security patches and features will not be received.
Evidence boundary
What the source does not prove
AWS states that this policy affects TypeScript type-level and build compatibility, not JavaScript runtime execution. AWS will build and test the SDK against compilers inside the support window and may not address issues specific to out-of-window versions. Existing projects can remain temporarily compatible by not updating the SDK, but that pinning path forfeits later SDK updates, security patches and features.
Lifecycle history
Dated event sequence
- Rolling support policy announced
AWS announced that SDK for JavaScript v3 would follow the DefinitelyTyped TypeScript support window plus a six-month grace period.
- First rolling compiler boundary
TypeScript 5.5 and earlier leave AWS SDK for JavaScript v3 support; projects must use a compiler still inside the rolling 2.5-year window to remain supported.
Evidence ledger
First-party sources
- 01Amazon Web Services — Updating TypeScript version support in AWS SDK for JavaScript v3
Official AWS Developer Tools Blog · 2026-07-15
Open official source ↗