diff --git a/envoyfilter/Cargo.toml b/envoyfilter/Cargo.toml
index 45e45bbf..4fbe3de5 100644
--- a/envoyfilter/Cargo.toml
+++ b/envoyfilter/Cargo.toml
@@ -2,7 +2,7 @@
 name = "intelligent-prompt-gateway"
 version = "0.1.0"
 authors = ["Katanemo Inc <info@katanemo.com>"]
-edition = "2018"
+edition = "2021"
 
 [lib]
 crate-type = ["cdylib"]
diff --git a/envoyfilter/README.md b/envoyfilter/README.md
index fa802255..022e8b1f 100644
--- a/envoyfilter/README.md
+++ b/envoyfilter/README.md
@@ -1,5 +1,11 @@
 # Envoy filter code for gateway
 
+## Add toolchain
+
+```sh
+$ rustup target add wasm32-wasi
+```
+
 ## Building
 
 ```sh