diff --git a/test/posthog/feature_flags_test.exs b/test/posthog/feature_flags_test.exs
index 057217e..d55e400 100644
--- a/test/posthog/feature_flags_test.exs
+++ b/test/posthog/feature_flags_test.exs
@@ -1,6 +1,7 @@
 defmodule PostHog.FeatureFlagsTest do
-  # group only works for Elixir 1.18, can't make it async until then
-  use PostHog.Case, async: false, group: PostHog
+  use PostHog.Case,
+    async: Version.match?(System.version(), ">= 1.18.0"),
+    group: PostHog
 
   @moduletag config: [supervisor_name: PostHog]
 
diff --git a/test/posthog_test.exs b/test/posthog_test.exs
index ce83d91..0786974 100644
--- a/test/posthog_test.exs
+++ b/test/posthog_test.exs
@@ -1,6 +1,7 @@
 defmodule PostHogTest do
-  # group only works for Elixir 1.18, can't make it async until then
-  use PostHog.Case, async: false, group: PostHog
+  use PostHog.Case,
+    async: Version.match?(System.version(), ">= 1.18.0"),
+    group: PostHog
 
   @moduletag config: [supervisor_name: PostHog]