diff --git a/hera_librarian/client.py b/hera_librarian/client.py
index abaf30a..279badc 100644
--- a/hera_librarian/client.py
+++ b/hera_librarian/client.py
@@ -90,8 +90,11 @@ class LibrarianClient:
     port: int
     user: str
     password: str
+    checksum_threads: int = 1
 
-    def __init__(self, host: str, port: int, user: str, password: str):
+    def __init__(
+        self, host: str, port: int, user: str, password: str, checksum_threads: int = 1
+    ):
         """
         Create a new LibrarianClient.
 
@@ -105,6 +108,8 @@ def __init__(self, host: str, port: int, user: str, password: str):
             The name of the user.
         password : str
             The password of the user.
+        checksum_threads : int
+            The number of threads to use for checksum computation. Default is 1.
         """
 
         if host[-1] == "/":
@@ -115,6 +120,7 @@ def __init__(self, host: str, port: int, user: str, password: str):
         self.port = port
         self.user = user
         self.password = password
+        self.checksum_threads = checksum_threads
 
     def __repr__(self):
         return f"Librarian Client ({self.user}) for {self.host}:{self.port}"
@@ -394,7 +400,9 @@ def upload(
             endpoint="upload/stage",
             request=UploadInitiationRequest(
                 upload_size=get_size_from_path(local_path),
-                upload_checksum=get_checksum_from_path(local_path, threads=1),
+                upload_checksum=get_checksum_from_path(
+                    local_path, threads=self.checksum_threads
+                ),
                 upload_name=dest_path.name,
                 destination_location=dest_path,
                 uploader=self.user,
diff --git a/hera_librarian/utils.py b/hera_librarian/utils.py
index fcdadbc..8cc8809 100644
--- a/hera_librarian/utils.py
+++ b/hera_librarian/utils.py
@@ -95,19 +95,11 @@ def individual(
 
 
 def _filehash(filepath, hashfunc):
-    hasher = hashfunc()
-    blocksize = 64 * 1024
-
     if not os.path.exists(filepath):
-        return hasher.hexdigest()
+        return hashfunc().hexdigest()
 
     with open(filepath, "rb") as fp:
-        while True:
-            data = fp.read(blocksize)
-            if not data:
-                break
-            hasher.update(data)
-    return hasher.hexdigest()
+        return hashlib.file_digest(fp, hashfunc).hexdigest()
 
 
 def _reduce_hash(hashlist, hashfunc):
diff --git a/pyproject.toml b/pyproject.toml
index 0ca20f1..b3eb5ed 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ exclude=["*tests*"]
 [project]
 name="hera_librarian"
 requires-python = ">=3.10"
-version = "5.0.1"
+version = "5.1.0"
 dependencies = [
     "alembic",
     "argon2-cffi",
diff --git a/tests/integration_test/test_secondary_server.py b/tests/integration_test/test_secondary_server.py
index cc561be..0f37805 100644
--- a/tests/integration_test/test_secondary_server.py
+++ b/tests/integration_test/test_secondary_server.py
@@ -19,7 +19,7 @@ def test_secondary_server_simple(
 
     response = test_client.post(
         "/api/v2/ping",
-        content=PingRequest().model_dump_json(),
+        json=PingRequest().model_dump(),
         auth=("admin", "password"),
     )