diff --git a/.github/workflows/run_test_case.yaml b/.github/workflows/run_test_case.yaml
index e841c1e..9c2313e 100644
--- a/.github/workflows/run_test_case.yaml
+++ b/.github/workflows/run_test_case.yaml
@@ -22,7 +22,7 @@ jobs:
           make eunit
           rm -f rebar.lock
           make cover
-      - uses: actions/upload-artifact@v1
+      - uses: actions/upload-artifact@v4
         with:
           name: cover
           path: _build/test/cover
diff --git a/README.md b/README.md
index e07b31e..2343f23 100644
--- a/README.md
+++ b/README.md
@@ -49,6 +49,7 @@ HOCON spec for reference: https://lightbend.github.io/config/
           ```
         - Use normal string with escape sequence.
           For example: `a = "line1\nline2\"\"\"\nline3\n"`
+- Environment variable interpolation is not supported.
 
 ## Schema