diff --git a/.travis.yml b/.travis.yml
index acf1af0282..33dc7803ed 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,7 @@
 matrix:
   include:
     - language: rust
-      rust: stable
+      rust: beta
       script:
         - cargo gen-kinds --verify
         - cargo gen-tests --verify
diff --git a/appveyor.yml b/appveyor.yml
index a6ba3b0e15..a32a1e7b8a 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -2,7 +2,7 @@ os: Visual Studio 2015
 
 install:
   - curl https://win.rustup.rs/ --output rustup-init.exe
-  - rustup-init -yv --default-toolchain stable --default-host x86_64-pc-windows-msvc
+  - rustup-init -yv --default-toolchain beta --default-host x86_64-pc-windows-msvc
   - set PATH=%PATH%;%USERPROFILE%\.cargo\bin
   - rustc -vV
   - cargo -vV