diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6f3ca5b3..8eb49035 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -125,11 +125,12 @@ jobs:
 
       - name: Setup LocalStack (AWS emulation)
         run: |
-          echo "LOCALSTACK_CONTAINER=$(docker run -d -p 4566:4566 localstack/localstack:4.0.3)" >> $GITHUB_ENV
+          echo "LOCALSTACK_CONTAINER=$(docker run -d -p 4566:4566 localstack/localstack:4.11.1)" >> $GITHUB_ENV
           echo "EC2_METADATA_CONTAINER=$(docker run -d -p 1338:1338 amazon/amazon-ec2-metadata-mock:v1.9.2 --imdsv2)" >> $GITHUB_ENV
           aws --endpoint-url=http://localhost:4566 s3 mb s3://test-bucket
           aws --endpoint-url=http://localhost:4566 s3 mb s3://test-bucket-for-spawn
           aws --endpoint-url=http://localhost:4566 s3 mb s3://test-bucket-for-checksum
+          aws --endpoint-url=http://localhost:4566 s3 mb s3://test-bucket-for-copy-if-not-exists
           aws --endpoint-url=http://localhost:4566 s3api create-bucket --bucket test-object-lock --object-lock-enabled-for-bucket
 
           KMS_KEY=$(aws --endpoint-url=http://localhost:4566 kms create-key --description "test key")
diff --git a/src/aws/client.rs b/src/aws/client.rs
index 63371875..150a47c2 100644
--- a/src/aws/client.rs
+++ b/src/aws/client.rs
@@ -701,24 +701,24 @@ impl S3Client {
             // If SSE-C is used, we must include the encryption headers in every upload request.
             request = request.with_encryption_headers();
         }
+
         let (parts, body) = request.send().await?.into_parts();
-        let checksum_sha256 = parts
-            .headers
-            .get(SHA256_CHECKSUM)
-            .and_then(|v| v.to_str().ok())
-            .map(|v| v.to_string());
-
-        let e_tag = match is_copy {
-            false => get_etag(&parts.headers).map_err(|source| Error::Metadata { source })?,
-            true => {
-                let response = body
-                    .bytes()
-                    .await
-                    .map_err(|source| Error::CreateMultipartResponseBody { source })?;
-                let response: CopyPartResult = quick_xml::de::from_reader(response.reader())
-                    .map_err(|source| Error::InvalidMultipartResponse { source })?;
-                response.e_tag
-            }
+        let (e_tag, checksum_sha256) = if is_copy {
+            let response = body
+                .bytes()
+                .await
+                .map_err(|source| Error::CreateMultipartResponseBody { source })?;
+            let response: CopyPartResult = quick_xml::de::from_reader(response.reader())
+                .map_err(|source| Error::InvalidMultipartResponse { source })?;
+            (response.e_tag, response.checksum_sha256)
+        } else {
+            let e_tag = get_etag(&parts.headers).map_err(|source| Error::Metadata { source })?;
+            let checksum_sha256 = parts
+                .headers
+                .get(SHA256_CHECKSUM)
+                .and_then(|v| v.to_str().ok())
+                .map(|v| v.to_string());
+            (e_tag, checksum_sha256)
         };
 
         let content_id = if self.config.checksum == Some(Checksum::SHA256) {
diff --git a/src/aws/mod.rs b/src/aws/mod.rs
index 3e658afc..cb66f9dc 100644
--- a/src/aws/mod.rs
+++ b/src/aws/mod.rs
@@ -553,6 +553,32 @@ mod tests {
         store.delete(&path).await.unwrap();
     }
 
+    #[tokio::test]
+    async fn copy_multipart_file_with_signature() {
+        maybe_skip_integration!();
+
+        let bucket = "test-bucket-for-copy-if-not-exists";
+        let store = AmazonS3Builder::from_env()
+            .with_bucket_name(bucket)
+            .with_checksum_algorithm(Checksum::SHA256)
+            .with_copy_if_not_exists(S3CopyIfNotExists::Multipart)
+            .build()
+            .unwrap();
+
+        let src = Path::parse("src.bin").unwrap();
+        let dst = Path::parse("dst.bin").unwrap();
+        store
+            .put(&src, PutPayload::from(vec![0u8; 100_000]))
+            .await
+            .unwrap();
+        if store.head(&dst).await.is_ok() {
+            store.delete(&dst).await.unwrap();
+        }
+        store.copy_if_not_exists(&src, &dst).await.unwrap();
+        store.delete(&src).await.unwrap();
+        store.delete(&dst).await.unwrap();
+    }
+
     #[tokio::test]
     async fn write_multipart_file_with_signature_object_lock() {
         maybe_skip_integration!();
diff --git a/src/client/s3.rs b/src/client/s3.rs
index a2221fbb..a1b113e0 100644
--- a/src/client/s3.rs
+++ b/src/client/s3.rs
@@ -98,6 +98,8 @@ pub(crate) struct InitiateMultipartUploadResult {
 pub(crate) struct CopyPartResult {
     #[serde(rename = "ETag")]
     pub e_tag: String,
+    #[serde(default, rename = "ChecksumSHA256")]
+    pub checksum_sha256: Option<String>,
 }
 
 #[derive(Debug, Serialize)]