diff --git a/Cargo.toml b/Cargo.toml
index c413e56c..1048dbe4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,7 @@ name = "h2"
 #   - html_root_url.
 # - Update CHANGELOG.md.
 # - Create git tag
-version = "0.3.22"
+version = "0.4.0-dev"
 license = "MIT"
 authors = [
   "Carl Lerche <me@carllerche.com>",
@@ -21,6 +21,8 @@ exclude = ["fixtures/**", "ci/**"]
 edition = "2018"
 rust-version = "1.63"
 
+publish = false
+
 [features]
 # Enables `futures::Stream` implementations for various types.
 stream = []