diff --git a/.gitignore b/.gitignore
index 975287e9..4baa4a10 100644
--- a/.gitignore
+++ b/.gitignore
@@ -137,6 +137,9 @@ venv.bak/
 .spyderproject
 .spyproject
 
+# VS Code settings
+.vscode/
+
 # Rope project settings
 .ropeproject
 
diff --git a/polarion_rest_api_client/data_models.py b/polarion_rest_api_client/data_models.py
index 1e7d80c6..41349bb4 100644
--- a/polarion_rest_api_client/data_models.py
+++ b/polarion_rest_api_client/data_models.py
@@ -3,6 +3,7 @@
 """Data model classes returned by the client."""
 from __future__ import annotations
 
+import base64
 import dataclasses
 import hashlib
 import json
@@ -110,8 +111,13 @@ def calculate_checksum(self) -> str:
         del data["checksum"]
         del data["id"]
 
-        for at in data["attachments"]:
-            del at["id"]
+        for attachment in data["attachments"]:
+            try:
+                attachment["content_bytes"] = base64.b64encode(
+                    attachment["content_bytes"]
+                ).decode("utf8")
+            except TypeError:
+                pass
 
         data = dict(sorted(data.items()))