diff --git a/simplexmq.cabal b/simplexmq.cabal
index 22a9005db..29a5b22d4 100644
--- a/simplexmq.cabal
+++ b/simplexmq.cabal
@@ -27,9 +27,6 @@ extra-source-files:
     README.md
     CHANGELOG.md
 
-if (os(darwin))
-  ghc-option: -DIOS
-
 library
   exposed-modules:
       Simplex.Messaging.Agent
diff --git a/src/Simplex/Messaging/Parsers.hs b/src/Simplex/Messaging/Parsers.hs
index 410c2e1a8..09cea28d1 100644
--- a/src/Simplex/Messaging/Parsers.hs
+++ b/src/Simplex/Messaging/Parsers.hs
@@ -98,7 +98,7 @@ enumJSON tagModifier =
     }
 
 sumTypeJSON :: (String -> String) -> J.Options
-#if defined(IOS)
+#if defined(darwin_HOST_OS)
 sumTypeJSON = singleFieldJSON
 #else
 sumTypeJSON = taggedObjectJSON