diff --git a/.github/workflows/conformance.yml b/.github/workflows/conformance.yml
index 7f083e5..641da80 100644
--- a/.github/workflows/conformance.yml
+++ b/.github/workflows/conformance.yml
@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby: ['3.1', '3.2', '3.3', '3.4']
+        ruby: ['3.1', '3.2', '3.3', '3.4', '4.0']
         puma: ['~> 6.0', '~> 7.0', '~> 8.0']
     env:
       FF_DEPENDENCY_TEST_PUMA: ${{ matrix.puma }}
diff --git a/.github/workflows/unit.yml b/.github/workflows/unit.yml
index 8cef7f7..20325e5 100644
--- a/.github/workflows/unit.yml
+++ b/.github/workflows/unit.yml
@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        ruby: ['3.1', '3.2', '3.3', '3.4']
+        ruby: ['3.1', '3.2', '3.3', '3.4', '4.0']
         flags: ["--only --test-unit", "--only --test-dependencies"]
         include:
           - os: ubuntu-latest
diff --git a/functions_framework.gemspec b/functions_framework.gemspec
index 7c0686b..e2e6bb7 100644
--- a/functions_framework.gemspec
+++ b/functions_framework.gemspec
@@ -46,6 +46,8 @@ version = ::FunctionsFramework::VERSION
 
   spec.required_ruby_version = ">= 3.1.0"
   spec.add_dependency "cloud_events", ">= 0.7.0", "< 2.a"
+  spec.add_dependency "logger", ">= 1.2.7.1", "< 2.a"
+  spec.add_dependency "ostruct", ">= 0.1.0", "< 1.a"
   spec.add_dependency "puma", ">= 4.3.0", "< 9.a"
   spec.add_dependency "rack", ">= 2.1", "< 4.a"