diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index e10a66e..9823d24 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -8,7 +8,14 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rust: [1.31.0, stable, beta, nightly]
+        rust: [
+          1.31.0, # MSRV
+          1.51.0,
+          1.60.0,
+          stable,
+          beta,
+          nightly,
+        ]
     steps:
       - uses: actions/checkout@v4
       - uses: actions/cache@v4
@@ -19,7 +26,6 @@ jobs:
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
-      - run: cargo build
       - run: ./ci/test_full.sh
 
   # try a target that doesn't have std at all
diff --git a/.github/workflows/master.yaml b/.github/workflows/master.yaml
index 68c4900..f6487bf 100644
--- a/.github/workflows/master.yaml
+++ b/.github/workflows/master.yaml
@@ -24,5 +24,4 @@ jobs:
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
-      - run: cargo build
       - run: ./ci/test_full.sh
diff --git a/.github/workflows/pr.yaml b/.github/workflows/pr.yaml
index 787f908..4e6aa37 100644
--- a/.github/workflows/pr.yaml
+++ b/.github/workflows/pr.yaml
@@ -20,7 +20,6 @@ jobs:
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}
-      - run: cargo build
       - run: ./ci/test_full.sh
 
   fmt:
diff --git a/ci/rustup.sh b/ci/rustup.sh
index fed3e45..18015d2 100755
--- a/ci/rustup.sh
+++ b/ci/rustup.sh
@@ -5,6 +5,6 @@
 set -ex
 
 ci=$(dirname $0)
-for version in 1.31.0 stable beta nightly; do
+for version in 1.31.0 1.51.0 1.60.0 stable beta nightly; do
     rustup run "$version" "$ci/test_full.sh"
 done
diff --git a/ci/test_full.sh b/ci/test_full.sh
index ae93944..b844a8f 100755
--- a/ci/test_full.sh
+++ b/ci/test_full.sh
@@ -30,6 +30,12 @@ fi
 FEATURES=()
 echo "Testing supported features: ${FEATURES[*]}"
 
+cargo generate-lockfile
+
+# num-traits 0.2.19 started using dep: features, which requires 1.60 and is
+# otherwise ignored down to 1.51, but we need a manual downgrade before that.
+check_version 1.51 || cargo update -p num-traits --precise 0.2.18
+
 set -x
 
 # test the default