diff --git a/graphix/channels.py b/graphix/channels.py
index dbea14f5..08a575a6 100644
--- a/graphix/channels.py
+++ b/graphix/channels.py
@@ -4,8 +4,8 @@
 
 import copy
 import itertools
+import sys
 import typing
-from collections.abc import Sequence
 from typing import TYPE_CHECKING, SupportsIndex
 
 import numpy as np
@@ -14,6 +14,11 @@
 from graphix import linalg_validations as lv
 from graphix.ops import Ops
 
+if sys.version_info >= (3, 9):
+    from collections.abc import Sequence
+else:
+    from typing import Sequence
+
 if TYPE_CHECKING:
     from collections.abc import Iterable