diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f5bcd7c3..346d50f8 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -36,7 +36,7 @@ jobs:
           # see https://github.com/rust-lang/mdBook/issues/1779
           - os: ubuntu-18.04
             tool: cargo-hack,cargo-llvm-cov,cargo-minimal-versions,parse-changelog,cross,nextest,shellcheck,shfmt,valgrind,wasm-pack,wasmtime,cargo-watch
-          - os: macos-10.15
+          - os: macos-11
             tool: cargo-hack,cargo-llvm-cov,cargo-minimal-versions,parse-changelog,cross,nextest,shellcheck,shfmt,wasm-pack,wasmtime,mdbook,cargo-watch
           - os: windows-2019
             tool: cargo-hack,cargo-llvm-cov,cargo-minimal-versions,parse-changelog,cross,nextest,cargo-watch