<!-- Do not manually edit this file. Use the `changelogger` tool. -->
November 1st, 2025
==================
**Breaking Changes:**
- :warning: ([smithy-rs#4367](https://github.com/smithy-lang/smithy-rs/issues/4367)) Upgrade MSRV to Rust 1.88.0.
**New this release:**
- :tada: ([aws-sdk-rust#1366](https://github.com/awslabs/aws-sdk-rust/issues/1366), @c-thiel) Add tags to `AssumeRoleProviderBuilder`
- :bug: ([smithy-rs#4352](https://github.com/smithy-lang/smithy-rs/issues/4352), [smithy-rs#4353](https://github.com/smithy-lang/smithy-rs/issues/4353)) Update clients to allow `initial-response` events to be accepted on event streams, even when know modeled initial response exists.
This is required for spec compliance, backwards compatibility, and compatibility with non-smithy-rs based servers that
MAY unconditionally send `initial-response` messages.
- :bug: ([smithy-rs#4265](https://github.com/smithy-lang/smithy-rs/issues/4265), [smithy-rs#4189](https://github.com/smithy-lang/smithy-rs/issues/4189)) Adds new `with_test_defaults_v2()` for all clients supporting region configuration which applies `us-east-1` as default region if not set by user. This allows `aws-smithy-mocks` to work for non AWS SDK generated clients. Also clarify `test-util` feature requirement when using `aws-smithy-mocks`.
- `aws-sdk-connectcases` (1.96.0): Added two new case rule types: Parent Child Field Options (restricts child field options based on parent field value) and Hidden (controls child field visibility based on parent field value). Both enable dynamic field behavior within templates.
- `aws-sdk-ec2` (1.178.0): Amazon VPC IP Address Manager (IPAM) now supports automated prefix list management, allowing you to create rules that automatically populate customer-managed prefix lists with CIDRs from your IPAM pools or AWS resources based on tags, Regions, or other criteria.