diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 3641a2df..0a1975d0 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -22,6 +22,7 @@ jobs:
     strategy:
       matrix:
         rust:
+          - 1.56  # MSRV, Rust 2021
           - stable
           - nightly
         features: