diff --git a/cobalt/__init__.py b/cobalt/__init__.py
index caeba1c..cae7f64 100644
--- a/cobalt/__init__.py
+++ b/cobalt/__init__.py
@@ -8,7 +8,7 @@
 from .portion import PortionStructure, Portion
 from .uri import FrbrUri
 
-__version__ = '9.0.0'
+__version__ = '9.0.1'
 
 __all__ = [
     'Act', 'AkomaNtosoDocument', 'Amendment', 'AmendmentEvent', 'AmendmentList', 'AmendmentStructure',
diff --git a/pyproject.toml b/pyproject.toml
index 9d1848b..26c48f5 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,7 +23,7 @@ classifiers = [
 ]
 dependencies = [
     "iso8601 >= 0.1",
-    "lxml>=3.4.1,<5.0.0",
+    "lxml>=3.4.1",
 ]
 dynamic = ["version"]