diff --git a/pyproject.toml b/pyproject.toml
index abad14d0..14cbf4ad 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "amazon-s3-encryption-client-python"
-version = "3.0.0"
+version = "4.0.0"
 description = "This library provides an S3 client that supports client-side encryption."
 authors = [
     {name = "AWS Crypto Tools", email = "aws-crypto-tools@amazon.com"}