diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index c55a647a..3687abce 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -26,7 +26,9 @@ jobs:
         rustup default ${{matrix.rust_channel}}
     - name: MSRV dependencies
       if: matrix.rust_channel == '1.42.0'
-      run: cargo update -p indexmap --precise 1.6.2
+      run: |
+        cargo update -p indexmap --precise 1.6.2
+        cargo update -p once_cell --precise 1.14.0
     - name: Build
       run: cargo build --verbose
     - name: Run tests