This version of Unity is unsupported.
Method group is Obsolete

EditorUserBuildSettings.symlinkLibraries

Obsolete EditorUserBuildSettings.symlinkLibraries is obsolete. Use EditorUserBuildSettings.symlinkSources instead.
Upgrade to symlinkSources
public static bool symlinkLibraries;

Description

Symlink runtime libraries with an iOS Xcode project.