diff --git a/MIGRATING.md b/MIGRATING.md
index 6694228..2c74b4c 100644
--- a/MIGRATING.md
+++ b/MIGRATING.md
@@ -8,6 +8,8 @@ There are a few breaking changes, but they should be easy to fix. If you have an
 
 ### Breaking changes
 
+3.x works with WebCrypto exclusively, which is only available on HTTPS and localhost. If you need access to the file over HTTP, you'll need to stay on 2.x.
+
 #### The CLI
 
 When encrypting `secret.html`, the CLI will now create a folder with your encrypted file `encrypted/secret.html`. It will not create a `secret_encrypted.html` file anymore.