diff --git a/flake.nix b/flake.nix
index 6b07d1f2e6..a827eabc56 100644
--- a/flake.nix
+++ b/flake.nix
@@ -121,7 +121,7 @@
                 # we need threaded here, otherwise all the queing logic doesn't work properly.
                 # for iOS we also use -staticlib, to get one rolled up library.
                 # still needs mac2ios patching of the archives.
-                ghcOptions = [ "-staticlib" "-threaded" ];
+                ghcOptions = [ "-staticlib" "-threaded" "-DIOS" ];
                 postInstall = ''
                   ${pkgs.tree}/bin/tree $out
                   mkdir -p $out/_pkg
@@ -148,7 +148,7 @@
                 # we need threaded here, otherwise all the queing logic doesn't work properly.
                 # for iOS we also use -staticlib, to get one rolled up library.
                 # still needs mac2ios patching of the archives.
-                ghcOptions = [ "-staticlib" "-threaded" ];
+                ghcOptions = [ "-staticlib" "-threaded" "-DIOS" ];
                 postInstall = ''
                   ${pkgs.tree}/bin/tree $out
                   mkdir -p $out/_pkg
diff --git a/simplex-chat.cabal b/simplex-chat.cabal
index d568e817a7..7f665785e3 100644
--- a/simplex-chat.cabal
+++ b/simplex-chat.cabal
@@ -16,9 +16,6 @@ license-file:   LICENSE
 build-type:     Simple
 extra-source-files:
     README.md
-    
-if (os(darwin))
-  ghc-option: -DIOS
 
 library
   exposed-modules: