diff --git a/.travis.yml b/.travis.yml
index b7ee145..05ea9e7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,7 +6,6 @@ rust:
   - stable
 os:
   - linux
-  - osx
 script:
   - cargo build
   - cargo test
diff --git a/Cargo.toml b/Cargo.toml
index ae233cd..6bee177 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 
 name = "string_cache"
-version = "0.3.0"  # Also update README.md when making a semver-breaking change
+version = "0.4.0"  # Also update README.md when making a semver-breaking change
 authors = [ "The Servo Project Developers" ]
 description = "A string interning library for Rust, developed as part of the Servo project."
 license = "MIT / Apache-2.0"
@@ -27,12 +27,9 @@ log-events = ["rustc-serialize"]
 # Use unstable features to optimize space and time (memory and CPU usage).
 unstable = []
 
-# HeapSizeOf support
-heap_size = ["heapsize"]
-
 [dependencies]
 lazy_static = "0.2"
-serde = "0.8"
+serde = "0.9"
 phf_shared = "0.7.4"
 debug_unreachable = "0.1.1"
 rustc-serialize = { version = "0.3", optional = true }
diff --git a/README.md b/README.md
index d244f69..43cf6fb 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ In `Cargo.toml`:
 
 ```toml
 [dependencies]
-string_cache = "0.3"
+string_cache = "0.4"
 ```
 
 In `lib.rs`:
@@ -31,7 +31,7 @@ In `Cargo.toml`:
 build = "build.rs"
 
 [dependencies]
-string_cache = "0.3"
+string_cache = "0.4"
 
 [build-dependencies]
 string_cache_codegen = "0.3"
diff --git a/src/atom.rs b/src/atom.rs
index 1b12148..25e258c 100644
--- a/src/atom.rs
+++ b/src/atom.rs
@@ -228,11 +228,6 @@ impl<Static: StaticAtomSet> Atom<Static> {
     pub fn get_hash(&self) -> u32 {
         ((self.unsafe_data >> 32) ^ self.unsafe_data) as u32
     }
-
-    pub fn with_str<F, Output>(&self, cb: F) -> Output
-                               where F: FnOnce(&str) -> Output {
-        cb(self)
-    }
 }
 
 impl<Static: StaticAtomSet> Default for Atom<Static> {
@@ -431,16 +426,16 @@ impl<Static: StaticAtomSet> AsRef<str> for Atom<Static> {
 }
 
 impl<Static: StaticAtomSet> Serialize for Atom<Static> {
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error> where S: Serializer {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer {
         let string: &str = self.as_ref();
         string.serialize(serializer)
     }
 }
 
 impl<Static: StaticAtomSet> Deserialize for Atom<Static> {
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error> where D: Deserializer {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error> where D: Deserializer {
         let string: String = try!(Deserialize::deserialize(deserializer));
-        Ok(Atom::from(&*string))
+        Ok(Atom::from(string))
     }
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index 6229344..b7961c3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -15,7 +15,7 @@
 
 #[cfg(all(test, feature = "unstable"))] extern crate test;
 #[cfg(feature = "log-events")] extern crate rustc_serialize;
-#[cfg(feature = "heapsize")] #[macro_use] extern crate heapsize;
+#[cfg(feature = "heapsize")] extern crate heapsize;
 #[cfg(test)] extern crate rand;
 #[macro_use] extern crate lazy_static;
 #[macro_use] extern crate debug_unreachable;