diff --git a/assets/scripts/darwin/add_firebase_build_phase.rb b/assets/scripts/darwin/add_firebase_build_phase.rb
index 9360822..22fc59d 100644
--- a/assets/scripts/darwin/add_firebase_build_phase.rb
+++ b/assets/scripts/darwin/add_firebase_build_phase.rb
@@ -21,8 +21,7 @@
 phase.shell_path = '/bin/sh'
 phase.shell_script = content
 phase.run_only_for_deployment_postprocessing = '0'
-phase.simple_attributes.find { |attribute| attribute.plist_name == 'outputPaths' }
-     .default_value << '$(SRCROOT)/Runner/GoogleService-Info.plist'
+phase.output_paths.append('$(SRCROOT)/Runner/GoogleService-Info.plist')
 
 target.build_phases.rotate!(-1)