diff --git a/README.md b/README.md
index 80bc788..67ba578 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@
   </p>
 
 [![Documentation](https://img.shields.io/badge/docs-master-blue)](https://mcaptcha.github.io/pow_sha256/pow_sha256/index.html)
-[![Documentation](https://img.shields.io/badge/docs-0.2.0-yellow)](https://mcaptcha.org/docs/api/pow-sha256)
+[![Documentation](https://img.shields.io/badge/docs-0.2.1-yellow)](https://mcaptcha.org/docs/api/pow-sha256)
 ![CI (Linux)](<https://github.com/mCaptcha/pow_sha256/workflows/CI%20(Linux)/badge.svg>)
 [![dependency status](https://deps.rs/repo/github/mCaptcha/pow_sha256/status.svg)](https://deps.rs/repo/github/mCaptcha/pow_sha256)
 <br />
@@ -13,6 +13,9 @@
 
 </div>
 
+**NOTE: All versions prior to 0.2.1 produce broken PoWs, upgrade to
+latest version**
+
 > pow_sha256's copy of `pow_sha256` by
 > [robkorn](https://github.com/robkorn/pow_sha256)
 > which is a modified version of [`pow` library](https://github.com/bddap/pow).