ST-2026-010 · SDKs, clients & toolchains
AWS ends support for the .NET SDK V3 and directs customers to V4
AWS SDK for .NET V3 reached end of support on 1 June 2026. Existing packages remain available, but V3 will receive no further service updates, security patches or bug fixes; AWS recommends migration to V4.
Previous state
AWS SDK for .NET V3 remained in its supported lifecycle, then maintenance mode, with at least critical fixes available before the final cutoff.
Current state
V3 remains downloadable but no longer receives new-service support, security patches or bug fixes; maintained development moves to AWS SDK for .NET V4.
Affected users
Who needs to care
Applications, libraries, deployment tools and internal platforms that still compile against AWS SDK for .NET V3 packages.
Required response
What to do
Inventory V3 package references, review the AWS V4 migration guide and breaking changes, update and test non-production workloads, then move production builds to supported V4 packages.
Evidence boundary
What the source does not prove
AWS says existing V3 applications should continue to function unless service behavior changes. End of support does not mean immediate runtime shutdown, but it does remove future compatibility, security and bug-fix coverage.
Lifecycle history
Dated event sequence
- Maintenance mode began
AWS limited V3 updates ahead of the final support cutoff.
- End of support
AWS stopped planning updates or releases for V3, including security and bug fixes.
Evidence ledger
First-party sources
- 01AWS Developer Tools Blog — AWS SDK for .NET V3 end-of-support announcement
Official SDK lifecycle announcement · 2026-06-01
Open official source ↗