diff --git a/readthedocs.yml b/readthedocs.yml
index 4c2aa92..c510ea6 100644
--- a/readthedocs.yml
+++ b/readthedocs.yml
@@ -15,7 +15,7 @@ build:
       - pip install --upgrade pip setuptools wheel
     post_install:
       # Verify installation
-      - python -c "import pyef; print(f'PyEF version: {pyef.__version__}')"
+      - python -c "import pyef; print('PyEF version:', pyef.__version__)"
       - pip list
 
 # Conda environment with documentation dependencies