Issue #3: Only change system setting immediately, if isDnsEnabled.

dns.xcodeproj/project.pbxproj

@@ -269,7 +269,7 @@
 				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPad = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPhone = "UIInterfaceOrientationPortrait UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
-				IPHONEOS_DEPLOYMENT_TARGET = 16.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -305,7 +305,7 @@
 				INFOPLIST_KEY_UILaunchScreen_Generation = YES;
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPad = "UIInterfaceOrientationPortrait UIInterfaceOrientationPortraitUpsideDown UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
 				INFOPLIST_KEY_UISupportedInterfaceOrientations_iPhone = "UIInterfaceOrientationPortrait UIInterfaceOrientationLandscapeLeft UIInterfaceOrientationLandscapeRight";
-				IPHONEOS_DEPLOYMENT_TARGET = 16.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",

dns/BlocklistOption.swift

@@ -6,6 +6,7 @@
 //
 
 import Foundation
+import NetworkExtension
 
 enum BlocklistOption: String, CaseIterable, Identifiable {
     case secure = "Secure"
@@ -66,4 +67,12 @@ enum BlocklistOption: String, CaseIterable, Identifiable {
             return "2001:db8::1"
         }
     }
+
+    var settings: NEDNSOverHTTPSSettings {
+        let settings = NEDNSOverHTTPSSettings(servers: [ipv4, ipv6])
+        settings.serverURL = URL(string: "https://\(server)/dns-query")
+        settings.matchDomains = [""]
+
+        return settings
+    }
 }

dns/HomeView.swift

@@ -48,7 +48,7 @@ struct HomeView: View {
     private let privacyPolicyURL = URL(string: "https://www.sr2.uk/privacy")!
 
     var body: some View {
-        NavigationStack {
+        NavigationCompat {
             List {
                 
                 // Main toggle section

dns/NavigationCompat.swift

@@ -0,0 +1,32 @@
+//
+//  NavigationCompat.swift
+//  dns
+//
+//  Created by Benjamin Erhart on 15.04.26.
+//
+import SwiftUI
+
+struct NavigationCompat<Content: View>: View {
+
+    let content: () -> Content
+
+    init(@ViewBuilder content: @escaping () -> Content) {
+        self.content = content
+    }
+
+    var body: some View {
+        if #available(iOS 16.0, macOS 13.0, *) {
+            NavigationStack {
+                content()
+            }
+        }
+        else {
+            NavigationView {
+                content()
+            }
+#if !os(macOS)
+            .navigationViewStyle(StackNavigationViewStyle())
+#endif
+        }
+    }
+}

dns/Settings.swift

@@ -0,0 +1,24 @@
+//
+//  Settings.swift
+//  dns
+//
+//  Created by Benjamin Erhart on 15.04.26.
+//
+
+import Foundation
+
+class Settings {
+
+    private static let blocklistKey = "blocklist"
+
+    private static let defaults = UserDefaults.standard
+
+    class var blocklist: BlocklistOption {
+        get {
+            BlocklistOption(rawValue: defaults.string(forKey: blocklistKey) ?? BlocklistOption.secure.rawValue) ?? .secure
+        }
+        set {
+            defaults.set(newValue.rawValue, forKey: blocklistKey)
+        }
+    }
+}

dns/ViewModel.swift

@@ -12,24 +12,27 @@ import OSLog
 
 class ViewModel: NSObject, ObservableObject {
 
-    // TODO: Store this in UserDefaults
     @Published
-    var blocklist: BlocklistOption = .secure
-
-    // TODO: Store this in UserDefaults
-    @Published
-    var isDnsEnabled = false {
+    var blocklist: BlocklistOption = .secure {
         didSet {
-            if !isProgrammaticChange {
+            Settings.blocklist = blocklist
+
+            if isDnsEnabled {
                 toggleDns()
             }
             else {
-                // Reset, so next one is recognized as coming from the user again.
                 isProgrammaticChange = false
             }
         }
     }
 
+    @Published
+    var isDnsEnabled = false {
+        didSet {
+            toggleDns()
+        }
+    }
+
     private var isProgrammaticChange = false
 
 
@@ -38,26 +41,51 @@ class ViewModel: NSObject, ObservableObject {
     private let log = Logger(subsystem: String(describing: ViewModel.self), category: String(describing: ViewModel.self))
 
 
+    override init() {
+        super.init()
+
+        isProgrammaticChange = true
+        blocklist = Settings.blocklist
+
+        Task {
+            do {
+                try await manager.loadFromPreferences()
+            }
+            catch {
+                log.error("Error loading preferences: \(error)")
+
+                return
+            }
+
+            if let settings = manager.dnsSettings {
+                for dnsServer in BlocklistOption.allCases {
+                    if settings.servers.contains(dnsServer.ipv4) {
+                        await MainActor.run {
+                            isProgrammaticChange = true
+                            blocklist = dnsServer
+                            isProgrammaticChange = true
+                            isDnsEnabled = true
+                        }
+
+                        break
+                    }
+                }
+            }
+        }
+    }
+
+
     func toggleDns() {
+        guard !isProgrammaticChange else {
+            // Reset, so next one is recognized as coming from the user again.
+            isProgrammaticChange = false
+
+            return
+        }
+
         Task {
             if isDnsEnabled {
-                do {
-                    try await manager.loadFromPreferences()
-                }
-                catch {
-                    log.error("Error loading preferences: \(error)")
-
-                    delayedToggle(false)
-
-                    return
-                }
-
-                let settings = NEDNSOverHTTPSSettings(servers: [blocklist.ipv4, blocklist.ipv6])
-                settings.serverURL = URL(string: "https://\(blocklist.server)")
-                settings.matchDomains = [""]
-
-
-                manager.dnsSettings = settings
+                manager.dnsSettings = blocklist.settings
                 manager.localizedDescription = blocklist.description
 
                 do {