diff --git a/ci/ci-tests.sh b/ci/ci-tests.sh
index 7a16b749200..dc72ae7cb8e 100755
--- a/ci/ci-tests.sh
+++ b/ci/ci-tests.sh
@@ -29,6 +29,12 @@ PIN_RELEASE_DEPS # pin the release dependencies in our main workspace
 # The quote crate switched to Rust edition 2021 starting with v1.0.31, i.e., has MSRV of 1.56
 [ "$RUSTC_MINOR_VERSION" -lt 56 ] && cargo update -p quote --precise "1.0.30" --verbose
 
+# The syn crate depends on too-new proc-macro2 starting with v2.0.33, i.e., has MSRV of 1.56
+if [ "$RUSTC_MINOR_VERSION" -lt 56 ]; then
+	SYN_2_DEP=$(grep -o '"syn 2.*' Cargo.lock | tr -d '",' | tr ' ' ':')
+	cargo update -p "$SYN_2_DEP" --precise "2.0.32" --verbose
+fi
+
 # The proc-macro2 crate switched to Rust edition 2021 starting with v1.0.66, i.e., has MSRV of 1.56
 [ "$RUSTC_MINOR_VERSION" -lt 56 ] && cargo update -p proc-macro2 --precise "1.0.65" --verbose