Evidence boundary: Existing applications may continue to run, but version 3 no longer receives AWS support, updates or security fixes.
What changes
AWS no longer maintains the v3 SDK line. New service support, bug fixes and security maintenance move to version 4.
Who is affected
- .NET applications that still reference AWS SDK v3 packages.
- Internal libraries that pin v3 dependencies.
- Teams whose deployment policy requires a vendor-supported SDK.
Timeline
End of support took effect on 1 June 2026.
Required action
- Inventory v3 package references and transitive dependencies.
- Review v4 migration notes and breaking changes.
- Upgrade, rebuild and regression-test AWS service integrations.
- Update support and software-composition records.
What is not affected
The AWS services called by the SDK continue. The end-of-support event concerns the v3 client library line.
PlatformTrace analysis
This is a support-lifecycle boundary rather than an immediate shutdown, but the security and maintenance risk increases for applications that remain on v3.
Sources
Corrections and updates
No correction is currently open. Material migration-guidance changes will be recorded as dated updates.