diff --git a/pyproject.toml b/pyproject.toml
index a223aadc9f7e2fb3d55af09da3048f735d6ab6ed..2818cf1e14ddaf25d6b565c2bc4dd8fd7a848255 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,6 +23,6 @@ classifiers=[
 [project.optional-dependencies]
 testing = [
     "pytest>=8.0",
-    "pytest-cov>=6.0",
+    "pytest-cov>=5,<6",  # Use pytest-cov version 5.x which supports Python 3.8
     "requests>=2.0"
 ]
\ No newline at end of file