diff --git a/.travis.yml b/.travis.yml
index a421a7b9334..49b35327950 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -36,7 +36,7 @@ matrix:
     # increased every 6 weeks or so when the first PR to use a new feature.
     - env: TARGET=x86_64-unknown-linux-gnu
            ALT=i686-unknown-linux-gnu
-      rust: 1.28.0
+      rust: 1.31.0
       script:
         - rustup toolchain install nightly
         - cargo +nightly generate-lockfile -Z minimal-versions
diff --git a/appveyor.yml b/appveyor.yml
index 282633ee071..6a2e257850b 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -11,7 +11,7 @@ install:
   - appveyor-retry appveyor DownloadFile https://win.rustup.rs/ -FileName rustup-init.exe
   - rustup-init.exe -y --default-host x86_64-pc-windows-msvc --default-toolchain nightly
   - set PATH=%PATH%;C:\Users\appveyor\.cargo\bin
-  - if defined MINIMAL_VERSIONS rustup toolchain install 1.28.0
+  - if defined MINIMAL_VERSIONS rustup toolchain install 1.31.0
   - if defined OTHER_TARGET rustup target add %OTHER_TARGET%
   - rustc -V
   - cargo -V
@@ -25,5 +25,5 @@ test_script:
   # we don't have ci time to run the full `cargo test` with `minimal-versions` like
   # - if defined MINIMAL_VERSIONS cargo +nightly generate-lockfile -Z minimal-versions && cargo +stable test
   # so we just run `cargo check --tests` like
-  - if defined MINIMAL_VERSIONS cargo +nightly generate-lockfile -Z minimal-versions && cargo +1.28.0 check --tests
+  - if defined MINIMAL_VERSIONS cargo +nightly generate-lockfile -Z minimal-versions && cargo +1.31.0 check --tests
   - if NOT defined MINIMAL_VERSIONS cargo test