diff --git a/serde/Cargo.toml b/serde/Cargo.toml
index 86fbe3c3..277c6798 100644
--- a/serde/Cargo.toml
+++ b/serde/Cargo.toml
@@ -11,6 +11,7 @@ keywords = ["serde", "serialization", "no_std"]
 categories = ["encoding"]
 readme = "../README.md"
 include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
+publish = false # this branch contains breaking changes
 
 [badges]
 travis-ci = { repository = "serde-rs/serde" }
diff --git a/serde_derive/Cargo.toml b/serde_derive/Cargo.toml
index 6a49f513..23b0a134 100644
--- a/serde_derive/Cargo.toml
+++ b/serde_derive/Cargo.toml
@@ -10,6 +10,7 @@ documentation = "https://serde.rs/codegen.html"
 keywords = ["serde", "serialization", "no_std"]
 readme = "../README.md"
 include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
+publish = false # this branch contains breaking changes
 
 [features]
 unstable = []
diff --git a/serde_test/Cargo.toml b/serde_test/Cargo.toml
index 63c442f5..8907f973 100644
--- a/serde_test/Cargo.toml
+++ b/serde_test/Cargo.toml
@@ -10,6 +10,7 @@ documentation = "https://docs.serde.rs/serde_test/"
 keywords = ["serde", "serialization"]
 readme = "../README.md"
 include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE-APACHE", "LICENSE-MIT"]
+publish = false # this branch contains breaking changes
 
 [dependencies]
 serde = { version = "0.9", path = "../serde" }