diff --git a/core-foundation/Cargo.toml b/core-foundation/Cargo.toml
index 98edd47..5c2d1d5 100644
--- a/core-foundation/Cargo.toml
+++ b/core-foundation/Cargo.toml
@@ -3,7 +3,7 @@ name = "core-foundation"
 description = "Bindings to Core Foundation for macOS"
 homepage = "https://github.com/servo/core-foundation-rs"
 repository = "https://github.com/servo/core-foundation-rs"
-version = "0.6.3"
+version = "0.6.4"
 authors = ["The Servo Project Developers"]
 license = "MIT / Apache-2.0"
 categories = ["os::macos-apis"]
diff --git a/core-foundation/src/dictionary.rs b/core-foundation/src/dictionary.rs
index d63a9ca..f954b71 100644
--- a/core-foundation/src/dictionary.rs
+++ b/core-foundation/src/dictionary.rs
@@ -58,6 +58,13 @@ impl<K, V> CFDictionary<K, V> {
         unsafe { CFDictionary::wrap_under_get_rule(self.0) }
     }
 
+    /// Returns a `CFMutableDictionary` pointing to the same underlying dictionary as this immutable one.
+    /// This should only be used when the underlying dictionary is mutable.
+    #[inline]
+    pub unsafe fn to_mutable(&self) -> CFMutableDictionary<K, V> {
+        CFMutableDictionary::wrap_under_get_rule(self.0 as CFMutableDictionaryRef)
+    }
+
     /// Returns the same dictionary, but with the types reset to void pointers.
     /// Equal to `to_untyped`, but is faster since it does not increment the retain count.
     #[inline]