diff --git a/pyproject.toml b/pyproject.toml
index c44a857..537cf77 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,7 +36,7 @@ classifiers = [
 dependencies = [
     "hatchling>=1.14.1,<1.30",
     "p2a>=0.1.1,<0.2",
-    "pkn>=0.3,<0.5",
+    "pkn>=0.3,<0.6",
 ]
 
 [project.optional-dependencies]