diff --git a/README.md b/README.md
index cc5add7..5b1c75a 100644
--- a/README.md
+++ b/README.md
@@ -11,6 +11,8 @@ You <-> Proxy client (Python) <-> Parasitized proxy server (Optional, PHP) <-> O
 ```
 For example, build a simple web debugging proxy on the shared servers.
 
+The default is stateless. You can use the stateful mode to avoid being constrained by transmission capacity limits (e.g., `max_upload_size`).
+
 ### Spam filtering strategy
 * [K-Anonymity](https://en.wikipedia.org/wiki/K-anonymity) test - Estimating whether the characters has been arranged by humans. (use [Have I Been Pwned](https://haveibeenpwned.com/Passwords))
 * Not CAPTCHA - Image spam containing characters that look very similar to [CAPTCHA](https://en.wikipedia.org/wiki/CAPTCHA). (use [TrueCaptcha](https://truecaptcha.org/))