diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 2ff8218..b470c2a 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.43.0"
+  ".": "0.44.0"
 }
diff --git a/.stats.yml b/.stats.yml
index 37e67d1..1d0622d 100644
--- a/.stats.yml
+++ b/.stats.yml
@@ -1,4 +1,4 @@
 configured_endpoints: 12
-openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/sequenzy/sequenzy-82ff31e45759730b6301de597bf2c06729584d65cd5e9716961ff3bb7a72a939.yml
-openapi_spec_hash: 564c0e85855f3e92ea07775a5fc9f172
+openapi_spec_url: https://storage.googleapis.com/stainless-sdk-openapi-specs/sequenzy/sequenzy-5f9701982d400470e967d7bbc9054439d7243987231445dc9a71f3c7809e6fc2.yml
+openapi_spec_hash: 2b3b6c678ef9af4378f15938586bf3cd
 config_hash: 51c1d1194ac58d8c8e3162839c8f84dd
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c751ddc..c3ba603 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 0.44.0 (2026-08-13)
+
+Full Changelog: [v0.43.0...v0.44.0](https://github.com/Sequenzy/sequenzy-typescript/compare/v0.43.0...v0.44.0)
+
+### Features
+
+* **api:** api update ([f0518a1](https://github.com/Sequenzy/sequenzy-typescript/commit/f0518a1c4a48aafb9aa99ff2100693c74912b1c1))
+
 ## 0.43.0 (2026-08-10)
 
 Full Changelog: [v0.42.0...v0.43.0](https://github.com/Sequenzy/sequenzy-typescript/compare/v0.42.0...v0.43.0)
diff --git a/package.json b/package.json
index 64bfe17..223366b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "sequenzy",
-  "version": "0.43.0",
+  "version": "0.44.0",
   "description": "The official TypeScript library for the Sequenzy API",
   "author": "Sequenzy <nic@sequenzy.com>",
   "types": "dist/index.d.ts",
diff --git a/src/resources/transactional.ts b/src/resources/transactional.ts
index 0aab2d5..6b4a319 100644
--- a/src/resources/transactional.ts
+++ b/src/resources/transactional.ts
@@ -54,8 +54,10 @@ export class Transactional extends APIResource {
    * **Attachments:**
    *
    * - Attachments can be provided as Base64-encoded content or URLs
-   * - Maximum total attachment size: 40MB per email
+   * - Maximum 10 attachments and 7MB total per email
    * - Any file type supported (PDFs, images, documents, etc.)
+   * - Set `contentId` on an attachment to embed it as an inline image referenced
+   *   from the HTML as `<img src="cid:VALUE">`
    *
    * A successful response means the email was accepted for background processing.
    * Transactional emails are not blocked by subscriber unsubscribe or double opt-in
@@ -370,7 +372,10 @@ export interface TransactionalSendParams {
    * - `content`: Base64-encoded file content
    * - `path`: URL to fetch the file from
    *
-   * Maximum total size: 40MB per email.
+   * Set `contentId` to embed the file as an inline image the HTML references with
+   * `<img src="cid:VALUE">` instead of attaching it.
+   *
+   * Maximum 10 attachments and 7MB total per email.
    */
   attachments?: Array<TransactionalSendParams.Attachment>;
 
@@ -493,7 +498,17 @@ export namespace TransactionalSendParams {
     content?: string;
 
     /**
-     * MIME type of the attachment (optional, auto-detected if not provided)
+     * Content-ID that embeds the file as an inline image instead of attaching it.
+     * Reference it from the HTML body as `<img src="cid:VALUE">`; the message is then
+     * sent as multipart/related, which is the only embedded-image form Gmail renders.
+     * If nothing in the HTML references the value, the file is sent as a normal
+     * attachment.
+     */
+    contentId?: string;
+
+    /**
+     * MIME type of the attachment (optional, auto-detected from the filename if not
+     * provided)
      */
     contentType?: string;
 
diff --git a/src/version.ts b/src/version.ts
index 771efed..6a69b90 100644
--- a/src/version.ts
+++ b/src/version.ts
@@ -1 +1 @@
-export const VERSION = '0.43.0'; // x-release-please-version
+export const VERSION = '0.44.0'; // x-release-please-version
diff --git a/tests/api-resources/transactional.test.ts b/tests/api-resources/transactional.test.ts
index 0cec3d3..4c4bd1a 100644
--- a/tests/api-resources/transactional.test.ts
+++ b/tests/api-resources/transactional.test.ts
@@ -57,6 +57,7 @@ describe('resource transactional', () => {
         {
           filename: 'invoice.pdf',
           content: 'JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC...',
+          contentId: 'ticket-qr',
           contentType: 'application/pdf',
           path: 'https://example.com/invoices/123.pdf',
         },