diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index fec61b3..0261088 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        toolchain: ["stable", "beta", "nightly", "1.36.0"]
+        toolchain: ["stable", "beta", "nightly", "1.57.0"]
         include:
           - toolchain: stable
             env:
@@ -21,17 +21,16 @@ jobs:
             env:
               DO_FUZZ: 1
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Install packages
-        run: sudo apt-get install -y binutils-dev libunwind8-dev libcurl4-openssl-dev libelf-dev libdw-dev cmake gcc libiberty-dev
+        if: matrix.os == 'ubuntu-latest'
+        run: sudo apt-get update -y && sudo apt-get install -y binutils-dev libunwind8-dev libcurl4-openssl-dev libelf-dev libdw-dev cmake gcc libiberty-dev
 
       - name: Install toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@master
         with:
-          profile: minimal
           toolchain: ${{ matrix.toolchain }}
-          override: true
 
       - name: Cargo build
         run: cargo build --verbose
@@ -46,10 +45,6 @@ jobs:
         if: matrix.toolchain == 'nightly'
         run: cargo check --verbose --no-default-features
 
-      - name: Cargo test w/ union
-        if: matrix.toolchain == 'beta'
-        run: cargo test --verbose --features union
-
       - name: Cargo test all features
         if: matrix.toolchain == 'nightly'
         run: cargo test --verbose --all-features
diff --git a/Cargo.toml b/Cargo.toml
index 745e986..4b90a21 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,6 +2,7 @@
 name = "smallvec"
 version = "1.9.0"
 edition = "2018"
+rust-version = "1.57"
 authors = ["The Servo Project Developers"]
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/servo/rust-smallvec"
diff --git a/scripts/run_miri.sh b/scripts/run_miri.sh
index 817928a..a5977df 100644
--- a/scripts/run_miri.sh
+++ b/scripts/run_miri.sh
@@ -17,5 +17,4 @@ rustup component add miri
 cargo miri setup
 
 cargo miri test --verbose
-cargo miri test --verbose --features union
 cargo miri test --verbose --all-features