diff --git a/CHANGELOG b/CHANGELOG
index 7bac93d..982cf0e 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,9 @@
+## v4.0.0
+- Use `is_hex_ascii` to optimize performance.
+- Add benchmark results.
+- Add `hex_bytes2hex_str` and `hex_bytes2hex_str_unchecked`.
+- Add fuzzing.
+
 ## v3.0.0
 - Break `hex_into` into `hex_into` and `hex_n_into`.
 - Break `hex_into_unchecked` into `hex_into_unchecked` and `hex_n_into_unchecked`.
diff --git a/Cargo.lock b/Cargo.lock
index 5bfa3e8..1875b58 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,7 +4,7 @@ version = 3
 
 [[package]]
 name = "array-bytes"
-version = "3.0.0"
+version = "4.0.0"
 dependencies = [
  "criterion",
  "faster-hex",
diff --git a/Cargo.toml b/Cargo.toml
index 91d15f8..44938ca 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,7 +18,7 @@ license = "GPL-3.0"
 name = "array-bytes"
 readme = "README.md"
 repository = "https://github.com/hack-ink/array-bytes"
-version = "3.0.0"
+version = "4.0.0"
 
 [badges]
 maintenance = { status = "actively-developed" }