diff --git a/README.md b/README.md
index 1d6fad71..1a142973 100644
--- a/README.md
+++ b/README.md
@@ -79,8 +79,11 @@ For more information please see `./CONTRIBUTING.md`.
 This library should always compile with any combination of features (minus
 `no-std`) on **Rust 1.41.1** or **Rust 1.47** with `no-std`.
 
-To build with the MSRV you will need to pin some dependencies, currently this is
-only `syn`, and can be achieved using `cargo update -p syn --precise 1.0.107`.
+To build with the MSRV you will need to pin some dependencies:
+```
+cargo update -p serde --precise 1.0.156
+cargo update -p syn --precise 1.0.107
+```
 
 ## Installing Rust
 
diff --git a/bitcoin/contrib/test.sh b/bitcoin/contrib/test.sh
index c4fc5107..1532c21c 100755
--- a/bitcoin/contrib/test.sh
+++ b/bitcoin/contrib/test.sh
@@ -25,6 +25,8 @@ fi
 
 # Pin dependencies as required if we are using MSRV toolchain.
 if cargo --version | grep "1\.41"; then
+    # 1.0.157 uses syn 2.0 which requires edition 2018
+    cargo update -p serde --precise 1.0.156
     # 1.0.108 uses `matches!` macro so does not work with Rust 1.41.1, bad `syn` no biscuit.
     cargo update -p syn --precise 1.0.107
 fi