diff --git a/environment-wasm-host.yml b/environment-wasm-host.yml
index 1ee5997c..4bb78c52 100644
--- a/environment-wasm-host.yml
+++ b/environment-wasm-host.yml
@@ -3,7 +3,7 @@ channels:
   - https://repo.prefix.dev/emscripten-forge-dev
   - https://repo.mamba.pm/conda-forge
 dependencies:
-  - nlohmann_json
+  - nlohmann_json=3.11.3
   - xeus-lite
   - xeus
   - CppInterOp