diff --git a/logprep/util/time.py b/logprep/util/time.py
index 32a209289..f02190611 100644
--- a/logprep/util/time.py
+++ b/logprep/util/time.py
@@ -4,8 +4,6 @@
 from typing import Union
 from zoneinfo import ZoneInfo
 
-import ciso8601
-
 from logprep.abc.exceptions import LogprepException
 
 UTC = ZoneInfo("UTC")
@@ -35,7 +33,7 @@ def from_string(cls, source: str, set_missing_utc: bool = True) -> datetime:
             datetime object
         """
         try:
-            time_object = ciso8601.parse_datetime(source)  # pylint: disable=c-extension-no-member
+            time_object = datetime.fromisoformat(source)  # pylint: disable=c-extension-no-member
             if set_missing_utc:
                 time_object = cls._set_utc_if_timezone_is_missing(time_object)
             return time_object
diff --git a/pyproject.toml b/pyproject.toml
index 5ece8ed2a..0f9fec7a2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -59,7 +59,6 @@ dependencies = [
   "aiohttp>=3.9.2",           # CVE-2024-23334
   "attrs",
   "certifi>=2023.7.22",       # CVE-2023-37920
-  "ciso8601",                 # fastest iso8601 datetime parser. can be removed after dropping support for python < 3.11
   "colorama",
   "confluent-kafka>2",
   "geoip2",
diff --git a/tests/unit/processor/timestamp_differ/test_timestamp_differ.py b/tests/unit/processor/timestamp_differ/test_timestamp_differ.py
index dd082562a..edb0bf6a8 100644
--- a/tests/unit/processor/timestamp_differ/test_timestamp_differ.py
+++ b/tests/unit/processor/timestamp_differ/test_timestamp_differ.py
@@ -343,7 +343,7 @@
             "subfield": {"field2": "2022-12-05 12:00:00"},
             "tags": ["_timestamp_differ_failure"],
         },
-        r".*ProcessingWarning.*Invalid character while parsing",
+        r".*ProcessingWarning.*Invalid isoformat string: 'non-timestamp'",
     ),
     (
         "diff between two timestamps with partial timestamp format match",