<!-- Do not manually edit this file. Use the `changelogger` tool. -->
June 27th, 2025
===============
**New this release:**
- :bug: (client) Fix hyper 1.x connection refused errors not marked as retryable
- (client, [smithy-rs#4186](https://github.com/smithy-lang/smithy-rs/issues/4186)) Make Rpc V2 CBOR a compatible protocol for `awsQuery` using `awsQueryCompatible` trait
"message":"Fix a bug where fields that were initially annotated with the `required` trait and later updated to use the `addedDefault` trait were not serialized when their values matched the default, even when the values were explicitly set. With this fix, fields with `addedDefault` are now always serialized.\n",
"message":"Promote `aws-smithy-mocks-experimental` to `aws-smithy-mocks`. This crate is now a recommended tool for testing\ngenerated SDK clients. This release includes several fixes as well as a new sequence builder API that can be\nused to test more complex scenarios such as retries.\n\n```rust\nuse aws_sdk_s3::operation::get_object::GetObjectOutput;\nuse aws_sdk_s3::config::retry::RetryConfig;\nuse aws_smithy_types::byte_stream::ByteStream;\nuse aws_smithy_mocks::{mock, mock_client, RuleMode};\n\n#[tokio::test]\nasync fn test_retry_behavior() {\n // Create a rule that returns 503 twice, then succeeds\n let retry_rule = mock!(aws_sdk_s3::Client::get_object)\n .sequence()\n .http_status(503, None)\n .times(2) // Return 503 HTTP status twice\n .output(|| GetObjectOutput::builder() // Finally return a successful output\n .body(ByteStream::from_static(b\"success\"))\n .build())\n .build();\n\n // Create a mocked client with the rule\n let s3 = mock_client!(\n aws_sdk_s3,\n RuleMode::Sequential,\n [&retry_rule],\n |client_builder| {\n client_builder.retry_config(RetryConfig::standard().with_max_attempts(3))\n }\n );\n\n // This should succeed after two retries\n let result = s3\n .get_object()\n .bucket(\"test-bucket\")\n .key(\"test-key\")\n .send()\n .await\n .expect(\"success after retries\");\n\n // Verify the response\n let data = result.body.collect().await.expect(\"successful read\").to_vec();\n assert_eq!(data, b\"success\");\n\n // Verify all responses were used\n assert_eq!(retry_rule.num_calls(), 3);\n}\n```\n",
"message":"Removing the `optimize_crc32_auto` feature flag from the `crc-fast` dependency of the `aws-smithy-checksums` crate since it was causing build issues for some customers.\n",
"message":"Introduce a new `repeatedly()` function to `aws-smithy-mocks` sequence builder to build mock rules that behave as an\ninfinite sequence.\n\n```rust\nlet rule = mock!(aws_sdk_s3::Client::get_object)\n .sequence()\n .http_status(503, None)\n .times(2) // repeat the last output twice before moving onto the next response in the sequence\n .output(|| GetObjectOutput::builder()\n .body(ByteStream::from_static(b\"success\"))\n .build()\n )\n .repeatedly() // repeat the last output forever\n .build();\n```\n",
