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 4a5582e4..b018a814 100644
--- a/polarion_rest_api_client/data_models.py
+++ b/polarion_rest_api_client/data_models.py
@@ -112,15 +112,18 @@ def calculate_checksum(self) -> str:
 
         attachments = data.pop("attachments")
 
+        for attachment in attachments:
+            try:
+                attachment["content_bytes"] = attachment[
+                    "content_bytes"
+                ].decode("utf-8")
+            except AttributeError:
+                pass
+
         data = dict(sorted(data.items()))
 
         converted = json.dumps(data).encode("utf8")
-        converted_attachments = json.dumps(attachments).encode("utf8")
-        self._checksum = (
-            hashlib.sha256(converted).hexdigest()
-            + " "
-            + hashlib.sha256(converted_attachments).hexdigest()
-        )
+        self._checksum = hashlib.sha256(converted).hexdigest()
         return self._checksum
 
     def get_current_checksum(self) -> str | None: