diff --git a/pyproject.toml b/pyproject.toml
index 3e46c72118..bc573fbe72 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,7 +41,7 @@ dependencies = [
     "scipy>=1.4.0,<2.0.0",
     "h5py>=3.1.0,<4.0.0",
     "opencv-python>=4.5.0,<5.0.0",
-    "pypdfium2>=4.11.0,<5.0.0",
+    "pypdfium2>=4.11.0,<6.0.0",
     "pyclipper>=1.2.0,<2.0.0",
     "shapely>=1.6.0,<3.0.0",
     "langdetect>=1.0.9,<2.0.0",