diff --git a/README.md b/README.md
index 534db82..c854ebb 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ Include the action in your workflow yaml:
 steps:
   - uses: actions/checkout@v3
   - name: Setup PDM
-    uses: pdm-project/setup-pdm@v3
+    uses: pdm-project/setup-pdm@v4
     # You are now able to use PDM in your workflow
   - name: Install dependencies
     run: pdm install
@@ -30,6 +30,7 @@ This action supports the following inputs:
 | Input                      | Default               | Description                                                                                                                          |
 | -------------------------- | --------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
 | `python-version`           | `3.x`                 | Version range or exact version of a Python version to use, using SemVer's version range syntax.                                      |
+| `python-version-file`      | `.python-version`     | File containing the Python version to use. Example: .`python-version`                                                                |
 | `architecture`             | `x64`                 | The target architecture (x86, x64) of the Python interpreter.                                                                        |
 | `allow-python-prereleases` | `false`               | Allow prerelease versions of Python to be installed.                                                                                 |
 | `token`                    | `${{ github.token }}` | Used to pull python distributions from actions/python-versions. Since there's a default, this is typically not supplied by the user. |