diff --git a/deepset_cloud_sdk/_s3/upload.py b/deepset_cloud_sdk/_s3/upload.py
index 96580074..1b27681c 100644
--- a/deepset_cloud_sdk/_s3/upload.py
+++ b/deepset_cloud_sdk/_s3/upload.py
@@ -7,7 +7,7 @@
 from http import HTTPStatus
 from pathlib import Path
 from types import TracebackType
-from typing import Any, Coroutine, List, Optional, Sequence, Type, Union
+from typing import Any, Coroutine, Dict, List, Optional, Sequence, Type, Union
 
 import aiofiles
 import aiohttp
@@ -94,7 +94,16 @@ def __init__(
         """
         self.connector = aiohttp.TCPConnector(limit=concurrency)
         self.semaphore = asyncio.BoundedSemaphore(concurrency)
-        self.limiter = Limiter(rate_limit, raise_when_fail=False, max_delay=Duration.SECOND * 1)
+
+        try:
+            # pyrate-limiter 3.x
+            self.limiter = Limiter(rate_limit, raise_when_fail=False, max_delay=Duration.SECOND * 1)
+            self._try_acquire_kwargs: Dict[str, Any] = {}
+        except TypeError:
+            # pyrate-limiter 4.0.0+ removed raise_when_fail and max_delay
+            self.limiter = Limiter(rate_limit)
+            self._try_acquire_kwargs = {"blocking": False}
+
         self.max_attempts = max_attempts
 
     async def __aenter__(self) -> "S3":
@@ -110,15 +119,15 @@ async def __aexit__(
         """Exit the context manager."""
         await self.connector.close()
 
-        # Handle limiter cleanup based on available methods
-        # Support both older and newer versions of pyrate_limiter
-        # In version 3.7.0, the dispose method was added to the Limiter class
-        # See diff here: https://github.com/vutran1710/PyrateLimiter/compare/v3.6.2...master
         try:
             list(map(self.limiter.dispose, self.limiter.buckets()))
         except AttributeError:
             pass
 
+    def _rate_limit_acquire(self) -> None:
+        """Acquire a rate limit token with backward compat for pyrate-limiter 3.x and 4.x."""
+        self.limiter.try_acquire("", **self._try_acquire_kwargs)
+
     async def _upload_file_with_retries(
         self,
         file_name: str,
@@ -158,7 +167,8 @@ async def _upload_file(
         file_data = self._build_file_data(content, aws_safe_name, aws_config)
 
         try:
-            self.limiter.try_acquire("")  # rate limit requests
+            self._rate_limit_acquire()
+
             async with client_session.post(
                 aws_config.url,
                 data=file_data,
@@ -172,7 +182,8 @@ async def _upload_file(
                     # for example during automatic redirects. See https://github.com/aio-libs/aiohttp/issues/5577
                     redirect_url = response.headers["Location"]
                     file_data = self._build_file_data(content, aws_safe_name, aws_config)
-                    self.limiter.try_acquire("")  # rate limit requests
+                    self._rate_limit_acquire()
+
                     async with client_session.post(
                         redirect_url,
                         json=file_data,