diff --git a/construct-stubs/core.pyi b/construct-stubs/core.pyi
index a5603ac..010f471 100644
--- a/construct-stubs/core.pyi
+++ b/construct-stubs/core.pyi
@@ -526,7 +526,7 @@ class Const(Subconstruct[SubconParsedType, SubconBuildTypes, ParsedType, BuildTy
     def __new__(
         cls,
         value: bytes,
-    ) -> Const[None, None, bytes, Bytes[bytes, int]]: ...
+    ) -> Const[None, None, bytes, t.Optional[bytes]]: ...
     @t.overload
     def __new__(
         cls,
diff --git a/requirements.txt b/requirements.txt
index 0836710..2d70b89 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,6 +1,6 @@
 construct==2.10.67
 pytest>=6.2.0
-numpy==1.20.*
+numpy==1.21.*
 arrow
 ruamel.yaml
 cloudpickle
diff --git a/tests/test_core.py b/tests/test_core.py
index 96b9b91..6f65772 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -634,7 +634,7 @@ def test_numpy() -> None:
 @pytest.mark.xfail(reason="docs stated that it throws StreamError, not true at all")
 def test_numpy_error() -> None:
     import numpy, io
-    numpy.load(io.BytesIO(b""))
+    numpy.load(io.BytesIO(b""))  # type: ignore
 
 def test_namedtuple() -> None:
     import collections