diff --git a/README.md b/README.md
index 8d67fafef829c795684a9b913831f6409cc0ddd3..e8aab51c8662eaaf40bd9d4a6eff9e0cfb92c77d 100644
--- a/README.md
+++ b/README.md
@@ -81,7 +81,7 @@ Contribution Guidelines
 -----------------------
 
 The SWIFT source code uses a variation of the 'Google' formatting style.
-The script 'format.sh' in the root directory applies the clang-format-10
+The script 'format.sh' in the root directory applies the clang-format-13
 tool with our style choices to all the SWIFT C source file. Please apply
 the formatting script to the files before submitting a pull request.