Using `attach_content` on Confluence Server with an existing attachement results in 415 HTTP error

[FSchumacher]

When I use the current version 5.0.4 (which contains #1666) on an on-prem confluence server and try to overwrite an existing attachment using attach_content I get a 415 HTTP error (version 4.x works fine with my code).

The exception is:

Traceback (most recent call last):
...
  File "/home/user/project/.venv/lib/python3.14/site-packages/atlassian/confluence/server/__init__.py", line 1253, in attach_file
    return self.attach_content(
           ~~~~~~~~~~~~~~~~~~~^
        infile,
        ^^^^^^^
    ...<5 lines>...
        comment=comment,
        ^^^^^^^^^^^^^^^^
    )
    ^
  File "/home/user/project/.venv/lib/python3.14/site-packages/atlassian/confluence/server/__init__.py", line 1178, in attach_content
    response = self.put(
        path=update_path,
    ...<2 lines>...
        files={"file": (name, content, content_type)},
    )
  File "/home/user/project/.venv/lib/python3.14/site-packages/atlassian/rest_client.py", line 942, in put
    response = self.request(
        "PUT",
    ...<7 lines>...
        advanced_mode=advanced_mode,
    )
  File "/home/user/project/.venv/lib/python3.14/site-packages/atlassian/confluence/server/__init__.py", line 120, in request
    return super(Server, self).request(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        method=method,
        ^^^^^^^^^^^^^^
    ...<10 lines>...
        allow_redirects=allow_redirects,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/home/user/project/.venv/lib/python3.14/site-packages/atlassian/rest_client.py", line 575, in request
    self.raise_for_status(response)
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/home/user/project/.venv/lib/python3.14/site-packages/atlassian/confluence/base.py", line 270, in raise_for_status
    raise HTTPError("\n".join(dict.fromkeys(messages)), response=response)
requests.exceptions.HTTPError: HTTP 415:

When I change the code of that method like the following diff:

index 6b39d38..6e61e4b 100644
--- a/atlassian/confluence/server/__init__.py
+++ b/atlassian/confluence/server/__init__.py
@@ -1175,15 +1175,24 @@ class Server(ConfluenceServerBase):
                     pass
 
                 if existing_attachment:
-                    # Update existing attachment using PUT on the specific attachment ID
                     attachment_id = existing_attachment["id"]
-                    update_path = f"rest/api/content/{attachment_id}"
-                    response = self.put(
-                        path=update_path,
-                        data=data,
-                        headers=headers,
-                        files={"file": (name, content, content_type)},
-                    )
+                    # Update existing attachment using PUT on the specific attachment ID
+                    if self.api_version == "1.0":
+                        update_path = f"{path}/{attachment_id}/data"
+                        response = self.post(
+                            path=update_path,
+                            data=data,
+                            headers=headers,
+                            files={"file": (name, content, content_type)},
+                        )
+                    else:
+                        update_path = f"rest/api/content/{attachment_id}"
+                        response = self.put(
+                            path=update_path,
+                            data=data,
+                            headers=headers,
+                            files={"file": (name, content, content_type)},
+                        )
                 else:
                     # Create new attachment using POST
                     response = self.post(

I can update the attachement without problems using my code.