diff --git a/.python-version b/.python-version
new file mode 100644
index 0000000..b326afb
--- /dev/null
+++ b/.python-version
@@ -0,0 +1 @@
+3.9.15
diff --git a/runtime.txt b/runtime.txt
deleted file mode 100644
index aaf66d8..0000000
--- a/runtime.txt
+++ /dev/null
@@ -1 +0,0 @@
-python-3.9.15