diff --git a/setup.cfg b/setup.cfg
index 34569e80..277246c1 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -49,6 +49,8 @@ install_requires =
     cffi>=1.9.1  # must be a setup and install requirement
     coloredlogs>=14.0  # strictly optional
     img2pdf>=0.3.0,<0.5  # pure Python
+    importlib-metadata>=4;python_version<'3.8'
+    importlib-resources>=5;python_version<'3.9'
     pdfminer.six!=20200720,>=20191110,<=20201018
     pikepdf>=2.10.0
     pikepdf<3;implementation_name=="pypy" and python_version=='3.6'