diff --git a/Config/BuildSettings.swift b/Config/BuildSettings.swift
index f045de597d..ee01e686a7 100644
--- a/Config/BuildSettings.swift
+++ b/Config/BuildSettings.swift
@@ -441,4 +441,25 @@ final class BuildSettings: NSObject {
     
     // MARK: - Alerts
     static let showUnverifiedSessionsAlert = true
+    
+    // MARK: - Sunset
+    
+    /// Meta data about the app that will replaces this one with Matrix 2.0 support.
+    struct ReplacementApp {
+        /// The app's display name, used in marketing banners.
+        let name = "Element X"
+        /// A link that will be opened to tell the user more about the new app, Matrix 2.0 and the migration.
+        let learnMoreURL = URL(string: "https://element.io")! // FIXME: This isn't the final URL.
+        /// The app's iTunes/product ID, used to show the App Store page in-app.
+        let productID = "1631335820"
+        /// A fallback URL that will be opened if there are any issues showing the App Store page in-app.
+        let appStoreURL = URL(string: "https://apps.apple.com/app/element-x-secure-chat-call/id1631335820")!
+    }
+    
+    /// Information about the Matrix 2.0 compatible app that will replace this one in the future.
+    ///
+    /// The presence of this setting acts as a feature flag to show marketing banners for the app
+    /// when it is detected that the homeserver is running Matrix 2.0. Set this to `nil` until you
+    /// are ready to migrate your users.
+    static let replacementApp: ReplacementApp? = .init()
 }
diff --git a/Podfile.lock b/Podfile.lock
index 34baf860f3..376efc3eb7 100644
--- a/Podfile.lock
+++ b/Podfile.lock
@@ -39,16 +39,16 @@ PODS:
   - LoggerAPI (1.9.200):
     - Logging (~> 1.1)
   - Logging (1.4.0)
-  - MatrixSDK (0.27.16):
-    - MatrixSDK/Core (= 0.27.16)
-  - MatrixSDK/Core (0.27.16):
+  - MatrixSDK (0.27.17):
+    - MatrixSDK/Core (= 0.27.17)
+  - MatrixSDK/Core (0.27.17):
     - AFNetworking (~> 4.0.0)
     - GZIP (~> 1.3.0)
     - libbase58 (~> 0.1.4)
     - MatrixSDKCrypto (= 0.4.3)
     - Realm (= 10.27.0)
     - SwiftyBeaver (= 1.9.5)
-  - MatrixSDK/JingleCallStack (0.27.16):
+  - MatrixSDK/JingleCallStack (0.27.17):
     - JitsiMeetSDKLite (= 8.1.2-lite)
     - MatrixSDK/Core
   - MatrixSDKCrypto (0.4.3)
@@ -179,7 +179,7 @@ SPEC CHECKSUMS:
   libPhoneNumber-iOS: 0a32a9525cf8744fe02c5206eb30d571e38f7d75
   LoggerAPI: ad9c4a6f1e32f518fdb43a1347ac14d765ab5e3d
   Logging: beeb016c9c80cf77042d62e83495816847ef108b
-  MatrixSDK: ce8f2cec670c2212144a129cc617d4144c89b97f
+  MatrixSDK: e3096b0b47f8a0bde6ae3f614f9c49e7e92b03ea
   MatrixSDKCrypto: 27bee960e0e8b3a3039f3f3e93dd2ec88299c77e
   ReadMoreTextView: 19147adf93abce6d7271e14031a00303fe28720d
   Realm: 9ca328bd7e700cc19703799785e37f77d1a130f2
diff --git a/Riot/Assets/Images.xcassets/Sunset/Contents.json b/Riot/Assets/Images.xcassets/Sunset/Contents.json
new file mode 100644
index 0000000000..73c00596a7
--- /dev/null
+++ b/Riot/Assets/Images.xcassets/Sunset/Contents.json
@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}
diff --git a/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/Contents.json b/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/Contents.json
new file mode 100644
index 0000000000..549a495b60
--- /dev/null
+++ b/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/Contents.json
@@ -0,0 +1,23 @@
+{
+  "images" : [
+    {
+      "filename" : "ElementXBannerIcon.png",
+      "idiom" : "universal",
+      "scale" : "1x"
+    },
+    {
+      "filename" : "ElementXBannerIcon@2x.png",
+      "idiom" : "universal",
+      "scale" : "2x"
+    },
+    {
+      "filename" : "ElementXBannerIcon@3x.png",
+      "idiom" : "universal",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}
diff --git a/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon.png b/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon.png
new file mode 100644
index 0000000000..3a12a28eb7
Binary files /dev/null and b/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon.png differ
diff --git a/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon@2x.png b/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon@2x.png
new file mode 100644
index 0000000000..563458c53b
Binary files /dev/null and b/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon@2x.png differ
diff --git a/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon@3x.png b/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon@3x.png
new file mode 100644
index 0000000000..6a65fa99a5
Binary files /dev/null and b/Riot/Assets/Images.xcassets/sunset_banner_icon.imageset/ElementXBannerIcon@3x.png differ
diff --git a/Riot/Assets/en.lproj/Vector.strings b/Riot/Assets/en.lproj/Vector.strings
index d0030805df..6adee1f2a7 100644
--- a/Riot/Assets/en.lproj/Vector.strings
+++ b/Riot/Assets/en.lproj/Vector.strings
@@ -98,6 +98,14 @@
 "accessibility_button_label" = "button";
 "accessibility_selected" = "selected";
 
+// MARK: Sunset
+"sunset_delegated_oidc_registration_not_supported_title" = "You can no longer create an account with %1$@ using this app";
+"sunset_delegated_oidc_registration_not_supported_message" = "Download %1$@ to use %2$@ for your account or choose a different homeserver.";
+"sunset_delegated_oidc_registration_not_supported_generic_error" = "You can no longer create an account with the entered homeserver using this app";
+"sunset_download_banner_title" = "Download %1$@";
+"sunset_download_banner_message" = "Faster, more secure, and packed with powerful collaboration tools.";
+"sunset_download_banner_learn_more" = "Learn more";
+
 // MARK: Onboarding
 "onboarding_splash_register_button_title" = "Create account";
 "onboarding_splash_login_button_title" = "I already have an account";
diff --git a/Riot/Generated/Images.swift b/Riot/Generated/Images.swift
index ce49740834..772a9957b4 100644
--- a/Riot/Generated/Images.swift
+++ b/Riot/Generated/Images.swift
@@ -355,6 +355,7 @@ internal class Asset: NSObject {
     internal static let voiceBroadcastTileMic = ImageAsset(name: "voice_broadcast_tile_mic")
     internal static let voiceBroadcastTimeLeft = ImageAsset(name: "voice_broadcast_time_left")
     internal static let launchScreenLogo = ImageAsset(name: "launch_screen_logo")
+    internal static let sunsetBannerIcon = ImageAsset(name: "sunset_banner_icon")
   }
   @objcMembers
   @objc(AssetSharedImages) internal class SharedImages: NSObject {
diff --git a/Riot/Generated/Strings.swift b/Riot/Generated/Strings.swift
index 5b168bcee2..d4dc0d142e 100644
--- a/Riot/Generated/Strings.swift
+++ b/Riot/Generated/Strings.swift
@@ -8743,6 +8743,30 @@ public class VectorL10n: NSObject {
   public static var suggest: String { 
     return VectorL10n.tr("Vector", "suggest") 
   }
+  /// You can no longer create an account with the entered homeserver using this app
+  public static var sunsetDelegatedOidcRegistrationNotSupportedGenericError: String { 
+    return VectorL10n.tr("Vector", "sunset_delegated_oidc_registration_not_supported_generic_error") 
+  }
+  /// Download %1$@ to use %2$@ for your account or choose a different homeserver.
+  public static func sunsetDelegatedOidcRegistrationNotSupportedMessage(_ p1: String, _ p2: String) -> String {
+    return VectorL10n.tr("Vector", "sunset_delegated_oidc_registration_not_supported_message", p1, p2)
+  }
+  /// You can no longer create an account with %1$@ using this app
+  public static func sunsetDelegatedOidcRegistrationNotSupportedTitle(_ p1: String) -> String {
+    return VectorL10n.tr("Vector", "sunset_delegated_oidc_registration_not_supported_title", p1)
+  }
+  /// Learn more
+  public static var sunsetDownloadBannerLearnMore: String { 
+    return VectorL10n.tr("Vector", "sunset_download_banner_learn_more") 
+  }
+  /// Faster, more secure, and packed with powerful collaboration tools.
+  public static var sunsetDownloadBannerMessage: String { 
+    return VectorL10n.tr("Vector", "sunset_download_banner_message") 
+  }
+  /// Download %1$@
+  public static func sunsetDownloadBannerTitle(_ p1: String) -> String {
+    return VectorL10n.tr("Vector", "sunset_download_banner_title", p1)
+  }
   /// Switch
   public static var `switch`: String { 
     return VectorL10n.tr("Vector", "switch") 
diff --git a/Riot/Modules/Authentication/AuthenticationCoordinator.swift b/Riot/Modules/Authentication/AuthenticationCoordinator.swift
index 357a7a54a8..74a0c3cf46 100644
--- a/Riot/Modules/Authentication/AuthenticationCoordinator.swift
+++ b/Riot/Modules/Authentication/AuthenticationCoordinator.swift
@@ -137,9 +137,13 @@ final class AuthenticationCoordinator: NSObject, AuthenticationCoordinatorProtoc
             return
         }
         
+        var showReplacementAppBanner = false
         do {
             // Start the flow (if homeserverAddress is nil, the default server will be used).
             try await authenticationService.startFlow(flow)
+        } catch RegistrationError.delegatedOIDCRequiresReplacementApp where BuildSettings.replacementApp != nil {
+            // The flow can continue, allowing the Registration Screen to display the banner.
+            showReplacementAppBanner = true
         } catch {
             MXLog.error("[AuthenticationCoordinator] start: Failed to start, showing server selection.")
             showServerSelectionScreen(for: flow)
@@ -151,7 +155,7 @@ final class AuthenticationCoordinator: NSObject, AuthenticationCoordinatorProtoc
             if authenticationService.state.homeserver.needsRegistrationFallback {
                 showFallback(for: flow)
             } else {
-                showRegistrationScreen()
+                showRegistrationScreen(showReplacementAppBanner: showReplacementAppBanner)
             }
         case .login:
             if authenticationService.state.homeserver.needsLoginFallback {
@@ -354,13 +358,12 @@ final class AuthenticationCoordinator: NSObject, AuthenticationCoordinatorProtoc
     // MARK: - Registration
     
     /// Shows the registration screen.
-    @MainActor private func showRegistrationScreen() {
+    @MainActor private func showRegistrationScreen(showReplacementAppBanner: Bool = false) {
         MXLog.debug("[AuthenticationCoordinator] showRegistrationScreen")
         let homeserver = authenticationService.state.homeserver
         let parameters = AuthenticationRegistrationCoordinatorParameters(navigationRouter: navigationRouter,
                                                                          authenticationService: authenticationService,
-                                                                         registrationFlow: homeserver.registrationFlow,
-                                                                         loginMode: homeserver.preferredLoginMode)
+                                                                         showReplacementAppBanner: showReplacementAppBanner)
         let coordinator = AuthenticationRegistrationCoordinator(parameters: parameters)
         coordinator.callback = { [weak self, weak coordinator] result in
             guard let self = self, let coordinator = coordinator else { return }
diff --git a/RiotSwiftUI/Modules/Authentication/Common/AuthenticationModels.swift b/RiotSwiftUI/Modules/Authentication/Common/AuthenticationModels.swift
index b15b5d7114..00faa8f94f 100644
--- a/RiotSwiftUI/Modules/Authentication/Common/AuthenticationModels.swift
+++ b/RiotSwiftUI/Modules/Authentication/Common/AuthenticationModels.swift
@@ -42,6 +42,7 @@ enum AuthenticationError: String, LocalizedError {
 /// Errors that can be thrown from `RegistrationWizard`
 enum RegistrationError: String, LocalizedError {
     case registrationDisabled
+    case delegatedOIDCRequiresReplacementApp
     case createAccountNotCalled
     case missingThreePIDData
     case missingThreePIDURL
@@ -58,6 +59,8 @@ enum RegistrationError: String, LocalizedError {
             return VectorL10n.authMsisdnValidationError
         case .invalidPhoneNumber:
             return VectorL10n.authenticationVerifyMsisdnInvalidPhoneNumber
+        case .delegatedOIDCRequiresReplacementApp:
+            return VectorL10n.sunsetDelegatedOidcRegistrationNotSupportedGenericError
         default:
             return VectorL10n.errorCommonMessage
         }
diff --git a/RiotSwiftUI/Modules/Authentication/Common/Service/MatrixSDK/AuthenticationService.swift b/RiotSwiftUI/Modules/Authentication/Common/Service/MatrixSDK/AuthenticationService.swift
index 47910e307d..b3a63ba0d2 100644
--- a/RiotSwiftUI/Modules/Authentication/Common/Service/MatrixSDK/AuthenticationService.swift
+++ b/RiotSwiftUI/Modules/Authentication/Common/Service/MatrixSDK/AuthenticationService.swift
@@ -148,8 +148,13 @@ class AuthenticationService: NSObject {
                 self.registrationWizard = registrationWizard
             } catch {
                 guard homeserver.preferredLoginMode.hasSSO, error as? RegistrationError == .registrationDisabled else {
-                    throw error
+                    if homeserver.preferredLoginMode.providesDelegatedOIDCCompatibility {
+                        throw RegistrationError.delegatedOIDCRequiresReplacementApp
+                    } else {
+                        throw error
+                    }
                 }
+                
                 // Continue without throwing when registration is disabled but SSO is available.
             }
         }
@@ -281,10 +286,13 @@ class AuthenticationService: NSObject {
         // Get the login flow
         let loginFlowResponse = try await client.getLoginSession()
         
-        let identityProviders = loginFlowResponse.flows?.compactMap { $0 as? MXLoginSSOFlow }.first?.identityProviders ?? []
+        let firstSSOFlow = loginFlowResponse.flows?.compactMap { $0 as? MXLoginSSOFlow }.first
+        let identityProviders = firstSSOFlow?.identityProviders ?? []
+        let providesDelegatedOIDCCompatibility = firstSSOFlow?.delegatedOIDCCompatibility ?? false
         return LoginFlowResult(supportedLoginTypes: loginFlowResponse.flows?.compactMap { $0 } ?? [],
                                ssoIdentityProviders: identityProviders.sorted { $0.name < $1.name }.map(\.ssoIdentityProvider),
-                               homeserverAddress: client.homeserver)
+                               homeserverAddress: client.homeserver, 
+                               providesDelegatedOIDCCompatibility: providesDelegatedOIDCCompatibility)
     }
     
     /// Perform a well-known request on the specified homeserver URL.
diff --git a/RiotSwiftUI/Modules/Authentication/Common/Service/MatrixSDK/LoginModels.swift b/RiotSwiftUI/Modules/Authentication/Common/Service/MatrixSDK/LoginModels.swift
index 50b7f94143..81803192c2 100644
--- a/RiotSwiftUI/Modules/Authentication/Common/Service/MatrixSDK/LoginModels.swift
+++ b/RiotSwiftUI/Modules/Authentication/Common/Service/MatrixSDK/LoginModels.swift
@@ -12,13 +12,15 @@ struct LoginFlowResult {
     let supportedLoginTypes: [MXLoginFlow]
     let ssoIdentityProviders: [SSOIdentityProvider]
     let homeserverAddress: String
+    let providesDelegatedOIDCCompatibility: Bool
     
     var loginMode: LoginMode {
         if supportedLoginTypes.contains(where: { $0.type == kMXLoginFlowTypeSSO }),
-           supportedLoginTypes.contains(where: { $0.type == kMXLoginFlowTypePassword }) {
+           supportedLoginTypes.contains(where: { $0.type == kMXLoginFlowTypePassword }),
+           !providesDelegatedOIDCCompatibility {
             return .ssoAndPassword(ssoIdentityProviders: ssoIdentityProviders)
         } else if supportedLoginTypes.contains(where: { $0.type == kMXLoginFlowTypeSSO }) {
-            return .sso(ssoIdentityProviders: ssoIdentityProviders)
+            return .sso(ssoIdentityProviders: ssoIdentityProviders, providesDelegatedOIDCCompatibility: providesDelegatedOIDCCompatibility)
         } else if supportedLoginTypes.contains(where: { $0.type == kMXLoginFlowTypePassword }) {
             return .password
         } else {
@@ -34,7 +36,7 @@ enum LoginMode {
     /// The homeserver supports login with a password.
     case password
     /// The homeserver supports login via one or more SSO providers.
-    case sso(ssoIdentityProviders: [SSOIdentityProvider])
+    case sso(ssoIdentityProviders: [SSOIdentityProvider], providesDelegatedOIDCCompatibility: Bool)
     /// The homeserver supports login with either a password or via an SSO provider.
     case ssoAndPassword(ssoIdentityProviders: [SSOIdentityProvider])
     /// The homeserver only allows login with unsupported mechanisms. Use fallback instead.
@@ -42,7 +44,7 @@ enum LoginMode {
     
     var ssoIdentityProviders: [SSOIdentityProvider]? {
         switch self {
-        case .sso(let ssoIdentityProviders), .ssoAndPassword(let ssoIdentityProviders):
+        case .sso(let ssoIdentityProviders, _), .ssoAndPassword(let ssoIdentityProviders):
             // Provide a backup for homeservers that support SSO but don't offer any identity providers
             // https://spec.matrix.org/latest/client-server-api/#client-login-via-sso
             return ssoIdentityProviders.count > 0 ? ssoIdentityProviders : [SSOIdentityProvider(id: "", name: "SSO", brand: nil, iconURL: nil)]
@@ -60,6 +62,15 @@ enum LoginMode {
         }
     }
     
+    var providesDelegatedOIDCCompatibility: Bool {
+        switch self {
+        case .sso(_, providesDelegatedOIDCCompatibility: true):
+            return true
+        default:
+            return false
+        }
+    }
+    
     var supportsPasswordFlow: Bool {
         switch self {
         case .password, .ssoAndPassword:
diff --git a/RiotSwiftUI/Modules/Authentication/Registration/AuthenticationRegistrationModels.swift b/RiotSwiftUI/Modules/Authentication/Registration/AuthenticationRegistrationModels.swift
index 1c7776687b..651f1c10b6 100644
--- a/RiotSwiftUI/Modules/Authentication/Registration/AuthenticationRegistrationModels.swift
+++ b/RiotSwiftUI/Modules/Authentication/Registration/AuthenticationRegistrationModels.swift
@@ -20,6 +20,8 @@ enum AuthenticationRegistrationViewModelResult: CustomStringConvertible {
     case continueWithSSO(SSOIdentityProvider)
     /// Continue using a fallback
     case fallback
+    /// Show the app store page for the replacement app.
+    case downloadReplacementApp(BuildSettings.ReplacementApp)
     
     /// A string representation of the result, ignoring any associated values that could leak PII.
     var description: String {
@@ -34,6 +36,8 @@ enum AuthenticationRegistrationViewModelResult: CustomStringConvertible {
             return "continueWithSSO: \(provider)"
         case .fallback:
             return "fallback"
+        case .downloadReplacementApp:
+            return "downloadReplacementApp"
         }
     }
 }
@@ -52,6 +56,8 @@ struct AuthenticationRegistrationViewState: BindableState {
     
     /// Data about the selected homeserver.
     var homeserver: AuthenticationHomeserverViewData
+    
+    var showReplacementAppBanner: Bool
     /// Whether a new homeserver is currently being loaded.
     var isLoading = false
     /// View state that can be bound to from SwiftUI.
@@ -85,7 +91,7 @@ struct AuthenticationRegistrationViewState: BindableState {
     
     /// Whether to show any SSO buttons.
     var showSSOButtons: Bool {
-        !homeserver.ssoIdentityProviders.isEmpty
+        !homeserver.ssoIdentityProviders.isEmpty && !showReplacementAppBanner
     }
     
     /// Whether the current `username` is invalid.
@@ -137,6 +143,8 @@ enum AuthenticationRegistrationViewAction {
     case continueWithSSO(SSOIdentityProvider)
     /// Continue using the fallback page
     case fallback
+    /// Show the app store page for the replacement app.
+    case downloadReplacementApp(BuildSettings.ReplacementApp)
 }
 
 enum AuthenticationRegistrationErrorType: Hashable {
@@ -151,6 +159,8 @@ enum AuthenticationRegistrationErrorType: Hashable {
     case invalidResponse
     /// The homeserver doesn't support registration.
     case registrationDisabled
+    /// The app doesn't support registration with this homeserver.
+    case registrationNotSupported
     /// An unknown error occurred.
     case unknown
 }
diff --git a/RiotSwiftUI/Modules/Authentication/Registration/AuthenticationRegistrationViewModel.swift b/RiotSwiftUI/Modules/Authentication/Registration/AuthenticationRegistrationViewModel.swift
index 753114d60a..3baaca2e44 100644
--- a/RiotSwiftUI/Modules/Authentication/Registration/AuthenticationRegistrationViewModel.swift
+++ b/RiotSwiftUI/Modules/Authentication/Registration/AuthenticationRegistrationViewModel.swift
@@ -19,9 +19,9 @@ class AuthenticationRegistrationViewModel: AuthenticationRegistrationViewModelTy
 
     // MARK: - Setup
 
-    init(homeserver: AuthenticationHomeserverViewData) {
+    init(homeserver: AuthenticationHomeserverViewData, showReplacementAppBanner: Bool) {
         let bindings = AuthenticationRegistrationBindings()
-        let viewState = AuthenticationRegistrationViewState(homeserver: homeserver, bindings: bindings)
+        let viewState = AuthenticationRegistrationViewState(homeserver: homeserver, showReplacementAppBanner: showReplacementAppBanner, bindings: bindings)
         
         super.init(initialViewState: viewState)
     }
@@ -44,6 +44,8 @@ class AuthenticationRegistrationViewModel: AuthenticationRegistrationViewModelTy
             Task { await callback?(.continueWithSSO(provider)) }
         case .fallback:
             Task { await callback?(.fallback) }
+        case .downloadReplacementApp(let replacementApp):
+            Task { await callback?(.downloadReplacementApp(replacementApp)) }
         }
     }
     
@@ -54,6 +56,10 @@ class AuthenticationRegistrationViewModel: AuthenticationRegistrationViewModelTy
     
     @MainActor func update(homeserver: AuthenticationHomeserverViewData) {
         state.homeserver = homeserver
+        
+        // Only the initial homeserver will ever need this, it isn't possible to update the
+        // server to another one that requires the replacement app as the selection will fail.
+        state.showReplacementAppBanner = false
     }
     
     @MainActor func update(username: String) {
@@ -82,6 +88,10 @@ class AuthenticationRegistrationViewModel: AuthenticationRegistrationViewModelTy
             state.bindings.alertInfo = AlertInfo(id: type,
                                                  title: VectorL10n.error,
                                                  message: VectorL10n.loginErrorRegistrationIsNotSupported)
+        case .registrationNotSupported:
+            state.bindings.alertInfo = AlertInfo(id: type,
+                                                 title: VectorL10n.error,
+                                                 message: VectorL10n.sunsetDelegatedOidcRegistrationNotSupportedGenericError)
         case .unknown:
             state.bindings.alertInfo = AlertInfo(id: type)
         }
diff --git a/RiotSwiftUI/Modules/Authentication/Registration/Coordinator/AuthenticationRegistrationCoordinator.swift b/RiotSwiftUI/Modules/Authentication/Registration/Coordinator/AuthenticationRegistrationCoordinator.swift
index 6f9051b583..2fa69bf4e4 100644
--- a/RiotSwiftUI/Modules/Authentication/Registration/Coordinator/AuthenticationRegistrationCoordinator.swift
+++ b/RiotSwiftUI/Modules/Authentication/Registration/Coordinator/AuthenticationRegistrationCoordinator.swift
@@ -7,15 +7,14 @@
 
 import CommonKit
 import MatrixSDK
+import StoreKit
 import SwiftUI
 
 struct AuthenticationRegistrationCoordinatorParameters {
     let navigationRouter: NavigationRouterType
     let authenticationService: AuthenticationService
-    /// The registration flow that is available for the chosen server.
-    let registrationFlow: RegistrationResult?
-    /// The login mode to allow SSO buttons to be shown when available.
-    let loginMode: LoginMode
+    /// Whether the authentication service is configured with a server uses MAS and so Element X should be used for registration instead.
+    let showReplacementAppBanner: Bool
 }
 
 enum AuthenticationRegistrationCoordinatorResult: CustomStringConvertible {
@@ -75,7 +74,7 @@ final class AuthenticationRegistrationCoordinator: Coordinator, Presentable {
         self.parameters = parameters
         
         let homeserver = parameters.authenticationService.state.homeserver
-        let viewModel = AuthenticationRegistrationViewModel(homeserver: homeserver.viewData)
+        let viewModel = AuthenticationRegistrationViewModel(homeserver: homeserver.viewData, showReplacementAppBanner: parameters.showReplacementAppBanner)
         authenticationRegistrationViewModel = viewModel
         
         let view = AuthenticationRegistrationScreen(viewModel: viewModel.context)
@@ -116,6 +115,8 @@ final class AuthenticationRegistrationCoordinator: Coordinator, Presentable {
                 self.callback?(.continueWithSSO(provider))
             case .fallback:
                 self.callback?(.fallback)
+            case .downloadReplacementApp(let replacementApp):
+                Task { await self.showReplacementAppStorePage(replacementApp) }
             }
         }
     }
@@ -242,6 +243,9 @@ final class AuthenticationRegistrationCoordinator: Coordinator, Presentable {
             switch registrationError {
             case .registrationDisabled:
                 authenticationRegistrationViewModel.displayError(.registrationDisabled)
+            case .delegatedOIDCRequiresReplacementApp:
+                // Edge case, is only shown in the user enters @alice:myserver.com to register directly on myserver.com
+                authenticationRegistrationViewModel.displayError(.registrationNotSupported)
             case .createAccountNotCalled, .missingThreePIDData, .missingThreePIDURL, .threePIDClientFailure, .threePIDValidationFailure, .waitingForThreePIDValidation, .invalidPhoneNumber:
                 // Shouldn't happen at this stage
                 authenticationRegistrationViewModel.displayError(.unknown)
@@ -289,4 +293,17 @@ final class AuthenticationRegistrationCoordinator: Coordinator, Presentable {
         let homeserver = authenticationService.state.homeserver
         authenticationRegistrationViewModel.update(homeserver: homeserver.viewData)
     }
+    
+    /// Presets the App Store page for the replacement app as a sheet.
+    @MainActor private func showReplacementAppStorePage(_ replacementApp: BuildSettings.ReplacementApp) async {
+        do {
+            let storeViewController = SKStoreProductViewController()
+            try await storeViewController.loadProduct(withParameters: [SKStoreProductParameterITunesItemIdentifier: replacementApp.productID])
+            authenticationRegistrationHostingController.present(storeViewController, animated: true)
+        } catch {
+            // Open the app store URL outside of the app as a fallback.
+            MXLog.warning("Unable to open the in-app store product page: \(error)")
+            await UIApplication.shared.open(replacementApp.appStoreURL)
+        }
+    }
 }
diff --git a/RiotSwiftUI/Modules/Authentication/Registration/MockAuthenticationRegistrationScreenState.swift b/RiotSwiftUI/Modules/Authentication/Registration/MockAuthenticationRegistrationScreenState.swift
index 8aae52ecaf..75a6375835 100644
--- a/RiotSwiftUI/Modules/Authentication/Registration/MockAuthenticationRegistrationScreenState.swift
+++ b/RiotSwiftUI/Modules/Authentication/Registration/MockAuthenticationRegistrationScreenState.swift
@@ -20,6 +20,7 @@ enum MockAuthenticationRegistrationScreenState: MockScreenState, CaseIterable {
     case passwordWithUsernameError
     case ssoOnly
     case fallback
+    case mas
 
     /// The associated screen
     var screenType: Any.Type {
@@ -31,22 +32,29 @@ enum MockAuthenticationRegistrationScreenState: MockScreenState, CaseIterable {
         let viewModel: AuthenticationRegistrationViewModel
         switch self {
         case .matrixDotOrg:
-            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockMatrixDotOrg)
+            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockMatrixDotOrg, showReplacementAppBanner: false)
         case .passwordOnly:
-            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockBasicServer)
+            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockBasicServer, showReplacementAppBanner: false)
         case .passwordWithCredentials:
-            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockBasicServer)
+            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockBasicServer, showReplacementAppBanner: false)
             viewModel.context.username = "alice"
             viewModel.context.password = "password"
             Task { await viewModel.confirmUsernameAvailability("alice") }
         case .passwordWithUsernameError:
-            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockBasicServer)
+            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockBasicServer, showReplacementAppBanner: false)
             viewModel.state.hasEditedUsername = true
             Task { await viewModel.displayError(.usernameUnavailable(VectorL10n.authInvalidUserName)) }
         case .ssoOnly:
-            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockEnterpriseSSO)
+            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockEnterpriseSSO, showReplacementAppBanner: false)
         case .fallback:
-            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockFallback)
+            viewModel = AuthenticationRegistrationViewModel(homeserver: .mockFallback, showReplacementAppBanner: false)
+        case .mas:
+            viewModel = AuthenticationRegistrationViewModel(homeserver: .init(address: "beta.matrix.org",
+                                                                              showLoginForm: false,
+                                                                              showRegistrationForm: false,
+                                                                              showQRLogin: false,
+                                                                              ssoIdentityProviders: []), // The initial discovery failed so the OIDC provider is not known.
+                                                            showReplacementAppBanner: true)
         }
         
         // can simulate service and viewModel actions here if needs be.
diff --git a/RiotSwiftUI/Modules/Authentication/Registration/Test/UI/AuthenticationRegistrationUITests.swift b/RiotSwiftUI/Modules/Authentication/Registration/Test/UI/AuthenticationRegistrationUITests.swift
index 70ac392546..a237d59247 100644
--- a/RiotSwiftUI/Modules/Authentication/Registration/Test/UI/AuthenticationRegistrationUITests.swift
+++ b/RiotSwiftUI/Modules/Authentication/Registration/Test/UI/AuthenticationRegistrationUITests.swift
@@ -15,6 +15,7 @@ class AuthenticationRegistrationUITests: MockScreenTestCase {
         let state = "matrix.org"
         validateRegistrationFormIsVisible(for: state)
         validateSSOButtonsAreShown(for: state)
+        validateSunsetBannersAreHidden(for: state)
         validateFallbackButtonIsHidden(for: state)
         
         validateUnknownUsernameAvailability(for: state)
@@ -27,6 +28,7 @@ class AuthenticationRegistrationUITests: MockScreenTestCase {
         let state = "a password only server"
         validateRegistrationFormIsVisible(for: state)
         validateSSOButtonsAreHidden(for: state)
+        validateSunsetBannersAreHidden(for: state)
         validateFallbackButtonIsHidden(for: state)
         
         validateNextButtonIsDisabled(for: state)
@@ -41,6 +43,7 @@ class AuthenticationRegistrationUITests: MockScreenTestCase {
         let state = "a password only server with credentials entered"
         validateRegistrationFormIsVisible(for: state)
         validateSSOButtonsAreHidden(for: state)
+        validateSunsetBannersAreHidden(for: state)
         validateFallbackButtonIsHidden(for: state)
         
         validateNextButtonIsEnabled(for: state)
@@ -55,6 +58,7 @@ class AuthenticationRegistrationUITests: MockScreenTestCase {
         let state = "a password only server with an invalid username"
         validateRegistrationFormIsVisible(for: state)
         validateSSOButtonsAreHidden(for: state)
+        validateSunsetBannersAreHidden(for: state)
         validateFallbackButtonIsHidden(for: state)
         
         validateNextButtonIsDisabled(for: state)
@@ -67,6 +71,7 @@ class AuthenticationRegistrationUITests: MockScreenTestCase {
         let state = "an SSO only server"
         validateRegistrationFormIsHidden(for: state)
         validateSSOButtonsAreShown(for: state)
+        validateSunsetBannersAreHidden(for: state)
         validateFallbackButtonIsHidden(for: state)
     }
     
@@ -76,9 +81,20 @@ class AuthenticationRegistrationUITests: MockScreenTestCase {
         let state = "fallback"
         validateRegistrationFormIsHidden(for: state)
         validateSSOButtonsAreHidden(for: state)
+        validateSunsetBannersAreHidden(for: state)
         validateFallbackButtonIsShown(for: state)
     }
     
+    func testSunsetBanner() {
+        app.goToScreenWithIdentifier(MockAuthenticationRegistrationScreenState.mas.title)
+        
+        let state = "mas"
+        validateRegistrationFormIsHidden(for: state)
+        validateSSOButtonsAreHidden(for: state)
+        validateSunsetBannersAreShown(for: state)
+        validateFallbackButtonIsShown(for: state, isEnabled: false)
+    }
+    
     /// Checks that the username and password text fields are shown along with the next button.
     func validateRegistrationFormIsVisible(for state: String) {
         let usernameTextField = app.textFields.element
@@ -108,12 +124,27 @@ class AuthenticationRegistrationUITests: MockScreenTestCase {
         XCTAssertFalse(fallbackButton.exists, "The fallback button should not be shown for \(state).")
     }
 
-    /// Checks that the fallback button is hidden.
-    func validateFallbackButtonIsShown(for state: String) {
+    /// Checks that the fallback button is shown.
+    func validateFallbackButtonIsShown(for state: String, isEnabled: Bool = true) {
         let fallbackButton = app.buttons["fallbackButton"]
 
         XCTAssertTrue(fallbackButton.exists, "The fallback button should be shown for \(state).")
-        XCTAssertTrue(fallbackButton.isEnabled, "The fallback button should be enabled for \(state).")
+        XCTAssertEqual(fallbackButton.isEnabled, isEnabled, "The fallback button should be \(isEnabled ? "enabled" : "disabled") for \(state).")
+    }
+    
+    /// Checks that the sunset banners are hidden.
+    func validateSunsetBannersAreHidden(for state: String) {
+        let downloadBanner = app.buttons["sunsetBanners"]
+
+        XCTAssertFalse(downloadBanner.exists, "The sunset banners should not be shown for \(state).")
+    }
+
+    /// Checks that the sunset banners are shown.
+    func validateSunsetBannersAreShown(for state: String) {
+        let downloadBanner = app.buttons["sunsetBanners"]
+
+        XCTAssertTrue(downloadBanner.exists, "The sunset banners should be shown for \(state).")
+        XCTAssertTrue(downloadBanner.isEnabled, "The sunset banners should be enabled for \(state).")
     }
     
     /// Checks that there is at least one SSO button shown on the screen.
diff --git a/RiotSwiftUI/Modules/Authentication/Registration/Test/Unit/AuthenticationRegistrationViewModelTests.swift b/RiotSwiftUI/Modules/Authentication/Registration/Test/Unit/AuthenticationRegistrationViewModelTests.swift
index 3cd212a847..4c0e5911fd 100644
--- a/RiotSwiftUI/Modules/Authentication/Registration/Test/Unit/AuthenticationRegistrationViewModelTests.swift
+++ b/RiotSwiftUI/Modules/Authentication/Registration/Test/Unit/AuthenticationRegistrationViewModelTests.swift
@@ -13,11 +13,10 @@ import XCTest
 @MainActor class AuthenticationRegistrationViewModelTests: XCTestCase {
     let defaultHomeserver = AuthenticationHomeserverViewData.mockMatrixDotOrg
     var viewModel: AuthenticationRegistrationViewModelProtocol!
-    var context: AuthenticationRegistrationViewModelType.Context!
+    var context: AuthenticationRegistrationViewModelType.Context { viewModel.context }
     
     @MainActor override func setUp() async throws {
-        viewModel = AuthenticationRegistrationViewModel(homeserver: defaultHomeserver)
-        context = viewModel.context
+        viewModel = AuthenticationRegistrationViewModel(homeserver: defaultHomeserver, showReplacementAppBanner: false)
     }
     
     func testMatrixDotOrg() {
@@ -27,6 +26,7 @@ import XCTest
         // Then the view state should contain a homeserver that matches matrix.org and shows SSO buttons.
         XCTAssertEqual(context.viewState.homeserver, homeserver, "The homeserver data should match the original.")
         XCTAssertTrue(context.viewState.showSSOButtons, "The SSO buttons should be shown.")
+        XCTAssertFalse(context.viewState.showReplacementAppBanner, "The sunset banner should not be shown.")
     }
     
     func testBasicServer() {
@@ -262,6 +262,28 @@ import XCTest
         // Then the view state should reflect that the homeserver is loading.
         XCTAssertEqual(context.username, localPart, "The username should match the value passed to the update method.")
     }
+    
+    func testSunsetBanner() async {
+        // Given a view model configured with a default homeserver that requires MAS (and the sunset banner).
+        let homeserver = AuthenticationHomeserverViewData(address: "beta.matrix.org",
+                                                          showLoginForm: false,
+                                                          showRegistrationForm: false,
+                                                          showQRLogin: false,
+                                                          ssoIdentityProviders: []) // The initial discovery would have failed so the OIDC provider is not known.
+        viewModel = AuthenticationRegistrationViewModel(homeserver: homeserver, showReplacementAppBanner: true)
+        XCTAssertEqual(context.viewState.homeserver, homeserver, "The homeserver data should match the original.")
+        XCTAssertTrue(context.viewState.showReplacementAppBanner, "The sunset banner should be shown.")
+        XCTAssertFalse(context.viewState.showSSOButtons, "The SSO buttons should not be shown.")
+        
+        // When selecting another server that doesn't require MAS.
+        let legacyHomeserver = AuthenticationHomeserverViewData.mockMatrixDotOrg
+        viewModel.update(homeserver: legacyHomeserver)
+        
+        // Then the banner should be removed and registration should be possible.
+        XCTAssertEqual(context.viewState.homeserver, legacyHomeserver, "The homeserver data should match the updated server.")
+        XCTAssertFalse(context.viewState.showReplacementAppBanner, "The sunset banner should no longer be visible.")
+        XCTAssertTrue(context.viewState.showSSOButtons, "The SSO buttons should now be visible.")
+    }
 }
 
 extension AuthenticationRegistrationViewState.UsernameAvailability: Equatable {
diff --git a/RiotSwiftUI/Modules/Authentication/Registration/View/AuthenticationRegistrationScreen.swift b/RiotSwiftUI/Modules/Authentication/Registration/View/AuthenticationRegistrationScreen.swift
index abca6dc3dc..512696cc02 100644
--- a/RiotSwiftUI/Modules/Authentication/Registration/View/AuthenticationRegistrationScreen.swift
+++ b/RiotSwiftUI/Modules/Authentication/Registration/View/AuthenticationRegistrationScreen.swift
@@ -50,9 +50,12 @@ struct AuthenticationRegistrationScreen: View {
                     ssoButtons
                         .padding(.top, 16)
                 }
+                
+                sunsetBanners
 
                 if !viewModel.viewState.homeserver.showRegistrationForm, !viewModel.viewState.showSSOButtons {
                     fallbackButton
+                        .disabled(viewModel.viewState.showReplacementAppBanner) // This button conveniently shows in the EX banner state, so use it as the disabled button.
                 }
             }
             .readableFrame()
@@ -134,6 +137,22 @@ struct AuthenticationRegistrationScreen: View {
             }
         }
     }
+    
+    @ViewBuilder
+    var sunsetBanners: some View {
+        if viewModel.viewState.showReplacementAppBanner, let replacementApp = BuildSettings.replacementApp {
+            VStack(spacing: 20) {
+                SunsetOIDCRegistrationBanner(homeserverAddress: viewModel.viewState.homeserver.address, 
+                                             replacementApp: replacementApp)
+                
+                SunsetDownloadBanner(replacementApp: replacementApp) {
+                    viewModel.send(viewAction: .downloadReplacementApp(replacementApp))
+                }
+            }
+            .padding(.bottom, 20)
+            .accessibilityIdentifier("sunsetBanners")
+        }
+    }
 
     /// A fallback button that can be used for login.
     var fallbackButton: some View {
diff --git a/RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionModels.swift b/RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionModels.swift
index eddcce981d..4ddd829ff9 100644
--- a/RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionModels.swift
+++ b/RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionModels.swift
@@ -14,15 +14,22 @@ enum AuthenticationServerSelectionViewModelResult {
     case confirm(homeserverAddress: String)
     /// Dismiss the view without using the entered address.
     case dismiss
+    /// Show the app store page for the replacement app.
+    case downloadReplacementApp(BuildSettings.ReplacementApp)
 }
 
 // MARK: View
 
 struct AuthenticationServerSelectionViewState: BindableState {
+    enum FooterError: Equatable {
+        case message(String)
+        case sunsetBanner
+    }
+    
     /// View state that can be bound to from SwiftUI.
     var bindings: AuthenticationServerSelectionBindings
     /// An error message to be shown in the text field footer.
-    var footerErrorMessage: String?
+    var footerError: FooterError?
     /// The flow that the screen is being used for.
     let flow: AuthenticationFlow
     /// Whether the screen is presented modally or within a navigation stack.
@@ -43,7 +50,7 @@ struct AuthenticationServerSelectionViewState: BindableState {
     
     /// The text field is showing an error.
     var isShowingFooterError: Bool {
-        footerErrorMessage != nil
+        footerError != nil
     }
     
     /// Whether it is possible to continue when tapping the confirmation button.
@@ -66,6 +73,8 @@ enum AuthenticationServerSelectionViewAction {
     case dismiss
     /// Clear any errors shown in the text field footer.
     case clearFooterError
+    /// Show the app store page for the replacement app.
+    case downloadReplacementApp(BuildSettings.ReplacementApp)
 }
 
 enum AuthenticationServerSelectionErrorType: Hashable {
@@ -73,4 +82,6 @@ enum AuthenticationServerSelectionErrorType: Hashable {
     case footerMessage(String)
     /// An error occurred when trying to open the EMS link
     case openURLAlert
+    /// An error message shown alongside a marketing banner to download the replacement app.
+    case requiresReplacementApp
 }
diff --git a/RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionViewModel.swift b/RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionViewModel.swift
index 89c329a3c1..703ea67f8a 100644
--- a/RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionViewModel.swift
+++ b/RiotSwiftUI/Modules/Authentication/ServerSelection/AuthenticationServerSelectionViewModel.swift
@@ -37,6 +37,8 @@ class AuthenticationServerSelectionViewModel: AuthenticationServerSelectionViewM
             Task { await callback?(.dismiss) }
         case .clearFooterError:
             Task { await clearFooterError() }
+        case .downloadReplacementApp(let replacementApp):
+            Task { await callback?(.downloadReplacementApp(replacementApp)) }
         }
     }
     
@@ -44,10 +46,14 @@ class AuthenticationServerSelectionViewModel: AuthenticationServerSelectionViewM
         switch type {
         case .footerMessage(let message):
             withAnimation {
-                state.footerErrorMessage = message
+                state.footerError = .message(message)
             }
         case .openURLAlert:
             state.bindings.alertInfo = AlertInfo(id: .openURLAlert, title: VectorL10n.roomMessageUnableOpenLinkErrorMessage)
+        case .requiresReplacementApp:
+            withAnimation {
+                state.footerError = .sunsetBanner
+            }
         }
     }
     
@@ -55,7 +61,7 @@ class AuthenticationServerSelectionViewModel: AuthenticationServerSelectionViewM
     
     /// Clear any errors shown in the text field footer.
     @MainActor private func clearFooterError() {
-        guard state.footerErrorMessage != nil else { return }
-        withAnimation { state.footerErrorMessage = nil }
+        guard state.footerError != nil else { return }
+        withAnimation { state.footerError = nil }
     }
 }
diff --git a/RiotSwiftUI/Modules/Authentication/ServerSelection/Coordinator/AuthenticationServerSelectionCoordinator.swift b/RiotSwiftUI/Modules/Authentication/ServerSelection/Coordinator/AuthenticationServerSelectionCoordinator.swift
index c5f15ecbb3..7ea5259e56 100644
--- a/RiotSwiftUI/Modules/Authentication/ServerSelection/Coordinator/AuthenticationServerSelectionCoordinator.swift
+++ b/RiotSwiftUI/Modules/Authentication/ServerSelection/Coordinator/AuthenticationServerSelectionCoordinator.swift
@@ -6,6 +6,7 @@
 //
 
 import CommonKit
+import StoreKit
 import SwiftUI
 
 struct AuthenticationServerSelectionCoordinatorParameters {
@@ -90,6 +91,8 @@ final class AuthenticationServerSelectionCoordinator: Coordinator, Presentable {
                 self.useHomeserver(homeserverAddress)
             case .dismiss:
                 self.callback?(.dismiss)
+            case .downloadReplacementApp(let replacementApp):
+                Task { await self.showReplacementAppStorePage(replacementApp) }
             }
         }
     }
@@ -119,17 +122,32 @@ final class AuthenticationServerSelectionCoordinator: Coordinator, Presentable {
                 stopLoading()
                 
                 callback?(.updated)
+            } catch RegistrationError.delegatedOIDCRequiresReplacementApp where BuildSettings.replacementApp != nil {
+                stopLoading()
+                authenticationServerSelectionViewModel.displayError(.requiresReplacementApp)
+            } catch let registrationError as RegistrationError {
+                stopLoading()
+                authenticationServerSelectionViewModel.displayError(.footerMessage(registrationError.localizedDescription))
             } catch {
                 stopLoading()
                 
-                if let error = error as? RegistrationError {
-                    authenticationServerSelectionViewModel.displayError(.footerMessage(error.localizedDescription))
-                } else {
-                    // Show the MXError message if possible otherwise use a generic server error
-                    let message = MXError(nsError: error)?.error ?? VectorL10n.authenticationServerSelectionGenericError
-                    authenticationServerSelectionViewModel.displayError(.footerMessage(message))
-                }
+                // Show the MXError message if possible otherwise use a generic server error
+                let message = MXError(nsError: error)?.error ?? VectorL10n.authenticationServerSelectionGenericError
+                authenticationServerSelectionViewModel.displayError(.footerMessage(message))
             }
         }
     }
+    
+    /// Presets the App Store page for the replacement app as a sheet.
+    @MainActor private func showReplacementAppStorePage(_ replacementApp: BuildSettings.ReplacementApp) async {
+        do {
+            let storeViewController = SKStoreProductViewController()
+            try await storeViewController.loadProduct(withParameters: [SKStoreProductParameterITunesItemIdentifier: replacementApp.productID])
+            authenticationServerSelectionHostingController.present(storeViewController, animated: true)
+        } catch {
+            // Open the app store URL outside of the app as a fallback.
+            MXLog.warning("Unable to open the in-app store product page: \(error)")
+            await UIApplication.shared.open(replacementApp.appStoreURL)
+        }
+    }
 }
diff --git a/RiotSwiftUI/Modules/Authentication/ServerSelection/MockAuthenticationServerSelectionScreenState.swift b/RiotSwiftUI/Modules/Authentication/ServerSelection/MockAuthenticationServerSelectionScreenState.swift
index c33e4587f2..c034261ec4 100644
--- a/RiotSwiftUI/Modules/Authentication/ServerSelection/MockAuthenticationServerSelectionScreenState.swift
+++ b/RiotSwiftUI/Modules/Authentication/ServerSelection/MockAuthenticationServerSelectionScreenState.swift
@@ -19,6 +19,7 @@ enum MockAuthenticationServerSelectionScreenState: MockScreenState, CaseIterable
     case invalidAddress
     case login
     case nonModal
+    case mas
     
     /// The associated screen
     var screenType: Any.Type {
@@ -50,6 +51,11 @@ enum MockAuthenticationServerSelectionScreenState: MockScreenState, CaseIterable
             viewModel = AuthenticationServerSelectionViewModel(homeserverAddress: "matrix.org",
                                                                flow: .register,
                                                                hasModalPresentation: false)
+        case .mas:
+            viewModel = AuthenticationServerSelectionViewModel(homeserverAddress: "beta.matrix.org",
+                                                               flow: .register,
+                                                               hasModalPresentation: false)
+            Task { await viewModel.displayError(.requiresReplacementApp) }
         }
         
         // can simulate service and viewModel actions here if needs be.
diff --git a/RiotSwiftUI/Modules/Authentication/ServerSelection/Test/UI/AuthenticationServerSelectionUITests.swift b/RiotSwiftUI/Modules/Authentication/ServerSelection/Test/UI/AuthenticationServerSelectionUITests.swift
index 868608ca78..4f1d49fd99 100644
--- a/RiotSwiftUI/Modules/Authentication/ServerSelection/Test/UI/AuthenticationServerSelectionUITests.swift
+++ b/RiotSwiftUI/Modules/Authentication/ServerSelection/Test/UI/AuthenticationServerSelectionUITests.swift
@@ -30,6 +30,9 @@ class AuthenticationServerSelectionUITests: MockScreenTestCase {
         
         let dismissButton = app.buttons["dismissButton"]
         XCTAssertTrue(dismissButton.exists, "The dismiss button should be shown during modal presentation.")
+        
+        let downloadBanner = app.buttons["sunsetBanners"]
+        XCTAssertFalse(downloadBanner.exists, "The sunset banners should not be shown when registering against a legacy homeserver.")
     }
     
     func testLoginState() {
@@ -76,4 +79,15 @@ class AuthenticationServerSelectionUITests: MockScreenTestCase {
         let confirmButton = app.buttons["confirmButton"]
         XCTAssertEqual(confirmButton.label, VectorL10n.next, "The confirm button should say Next when not in modal presentation.")
     }
+    
+    func testSunsetBanners() {
+        app.goToScreenWithIdentifier(MockAuthenticationServerSelectionScreenState.mas.title)
+        
+        let downloadBanner = app.buttons["sunsetBanners"]
+        XCTAssertTrue(downloadBanner.exists, "The sunset banners should be shown when registering against a homeserver with MAS.")
+        
+        let confirmButton = app.buttons["confirmButton"]
+        XCTAssertTrue(confirmButton.exists, "The confirm button should always be shown.")
+        XCTAssertFalse(confirmButton.isEnabled, "The confirm button should be disabled when there is an error.")
+    }
 }
diff --git a/RiotSwiftUI/Modules/Authentication/ServerSelection/Test/Unit/AuthenticationServerSelectionViewModelTests.swift b/RiotSwiftUI/Modules/Authentication/ServerSelection/Test/Unit/AuthenticationServerSelectionViewModelTests.swift
index 5fd2ed7cc7..d3036bf981 100644
--- a/RiotSwiftUI/Modules/Authentication/ServerSelection/Test/Unit/AuthenticationServerSelectionViewModelTests.swift
+++ b/RiotSwiftUI/Modules/Authentication/ServerSelection/Test/Unit/AuthenticationServerSelectionViewModelTests.swift
@@ -24,7 +24,7 @@ class AuthenticationServerSelectionViewModelTests: XCTestCase {
 
     @MainActor func testErrorMessage() async throws {
         // Given a new instance of the view model.
-        XCTAssertNil(context.viewState.footerErrorMessage, "There should not be an error message for a new view model.")
+        XCTAssertNil(context.viewState.footerError, "There should not be an error message for a new view model.")
         XCTAssertFalse(context.viewState.isShowingFooterError, "There should not be an error shown.")
         
         // When an error occurs.
@@ -32,7 +32,7 @@ class AuthenticationServerSelectionViewModelTests: XCTestCase {
         viewModel.displayError(.footerMessage(message))
         
         // Then the footer should now be showing an error.
-        XCTAssertEqual(context.viewState.footerErrorMessage, message, "The error message should be stored.")
+        XCTAssertEqual(context.viewState.footerError, .message(message), "The error message should be stored.")
         XCTAssertTrue(context.viewState.isShowingFooterError, "There should be an error shown.")
         
         // And when clearing the error.
@@ -42,7 +42,31 @@ class AuthenticationServerSelectionViewModelTests: XCTestCase {
         await Task.yield()
         
         // Then the error message should now be removed.
-        XCTAssertNil(context.viewState.footerErrorMessage, "The error message should have been cleared.")
+        XCTAssertNil(context.viewState.footerError, "The error message should have been cleared.")
+        XCTAssertFalse(context.viewState.isShowingFooterError, "There should not be an error shown anymore.")
+    }
+    
+    @MainActor func testSunsetBanner() async throws {
+        // Given a new instance of the view model.
+        XCTAssertNil(context.viewState.footerError, "There should not be an error for a new view model.")
+        XCTAssertFalse(context.viewState.isShowingFooterError, "There should not be an error shown.")
+        
+        // When an error occurs.
+        let message = "Unable to contact server."
+        viewModel.displayError(.requiresReplacementApp)
+        
+        // Then the footer should now be showing an error.
+        XCTAssertEqual(context.viewState.footerError, .sunsetBanner, "The banner should be shown.")
+        XCTAssertTrue(context.viewState.isShowingFooterError, "There should be an error shown.")
+        
+        // And when clearing the error.
+        context.send(viewAction: .clearFooterError)
+        
+        // Wait for the action to spawn a Task on the main actor as the Context protocol doesn't support actors.
+        await Task.yield()
+        
+        // Then the error message should now be removed.
+        XCTAssertNil(context.viewState.footerError, "The error should have been cleared.")
         XCTAssertFalse(context.viewState.isShowingFooterError, "There should not be an error shown anymore.")
     }
 }
diff --git a/RiotSwiftUI/Modules/Authentication/ServerSelection/View/AuthenticationServerSelectionScreen.swift b/RiotSwiftUI/Modules/Authentication/ServerSelection/View/AuthenticationServerSelectionScreen.swift
index dd01b6e7ff..2b8c1e1879 100644
--- a/RiotSwiftUI/Modules/Authentication/ServerSelection/View/AuthenticationServerSelectionScreen.swift
+++ b/RiotSwiftUI/Modules/Authentication/ServerSelection/View/AuthenticationServerSelectionScreen.swift
@@ -70,14 +70,10 @@ struct AuthenticationServerSelectionScreen: View {
     var serverForm: some View {
         VStack(alignment: .leading, spacing: 12) {
             VStack(spacing: 8) {
-                if #available(iOS 15.0, *) {
-                    textField
-                        .onSubmit(submit)
-                } else {
-                    textField
-                }
+                textField
+                    .onSubmit(submit)
                 
-                if let errorMessage = viewModel.viewState.footerErrorMessage {
+                if case let .message(errorMessage) = viewModel.viewState.footerError {
                     Text(errorMessage)
                         .font(theme.fonts.footnote)
                         .foregroundColor(textFieldFooterColor)
@@ -86,6 +82,8 @@ struct AuthenticationServerSelectionScreen: View {
                 }
             }
             
+            sunsetBanners
+            
             Button(action: submit) {
                 Text(viewModel.viewState.buttonTitle)
             }
@@ -95,7 +93,6 @@ struct AuthenticationServerSelectionScreen: View {
         }
     }
     
-    /// The text field, extracted for iOS 15 modifiers to be applied.
     var textField: some View {
         TextField(VectorL10n.authenticationServerSelectionServerUrl, text: $viewModel.homeserverAddress) {
             isEditingTextField = $0
@@ -109,6 +106,23 @@ struct AuthenticationServerSelectionScreen: View {
         .accessibilityIdentifier("addressTextField")
     }
     
+    @ViewBuilder
+    var sunsetBanners: some View {
+        if viewModel.viewState.footerError == .sunsetBanner, let replacementApp = BuildSettings.replacementApp {
+            VStack(spacing: 16) {
+                SunsetOIDCRegistrationBanner(homeserverAddress: viewModel.homeserverAddress, 
+                                             replacementApp: replacementApp)
+                
+                SunsetDownloadBanner(replacementApp: replacementApp) {
+                    viewModel.send(viewAction: .downloadReplacementApp(replacementApp))
+                }
+            }
+            .padding(.vertical, 4)
+            .padding(.bottom, 16)
+            .accessibilityIdentifier("sunsetBanners")
+        }
+    }
+    
     @ToolbarContentBuilder
     var toolbar: some ToolbarContent {
         ToolbarItem(placement: .cancellationAction) {
diff --git a/RiotSwiftUI/Modules/Common/Sunset/SunsetDownloadBanner.swift b/RiotSwiftUI/Modules/Common/Sunset/SunsetDownloadBanner.swift
new file mode 100644
index 0000000000..f50b1fb391
--- /dev/null
+++ b/RiotSwiftUI/Modules/Common/Sunset/SunsetDownloadBanner.swift
@@ -0,0 +1,66 @@
+//
+// Copyright 2025 New Vector Ltd
+//
+// SPDX-License-Identifier: AGPL-3.0-only
+// Please see LICENSE in the repository root for full details.
+//
+
+import SwiftUI
+
+struct SunsetDownloadBanner: View {
+    @Environment(\.theme) private var theme
+    
+    let replacementApp: BuildSettings.ReplacementApp
+    let action: () -> Void
+    
+    var body: some View {
+        Button(action: action) {
+            HStack(alignment: .top, spacing: 13) {
+                Image(Asset.Images.sunsetBannerIcon.name)
+                    .clipShape(RoundedRectangle(cornerRadius: 15.2))
+                
+                VStack(alignment: .leading, spacing: 4) {
+                    Text(VectorL10n.sunsetDownloadBannerTitle(replacementApp.name))
+                        .font(theme.fonts.title3SB)
+                        .foregroundStyle(theme.colors.primaryContent)
+                    
+                    Text(VectorL10n.sunsetDownloadBannerMessage)
+                        .font(theme.fonts.callout)
+                        .foregroundStyle(theme.colors.secondaryContent)
+                    
+                    // Using a button rather than an attributed string so that it animates on tap.
+                    Button(VectorL10n.sunsetDownloadBannerLearnMore) {
+                        UIApplication.shared.open(replacementApp.learnMoreURL)
+                    }
+                    .font(theme.fonts.bodySB)
+                    .tint(theme.colors.links)
+                    .padding(.top, 4)
+                }
+                .multilineTextAlignment(.leading)
+            }
+            .frame(maxWidth: .infinity, alignment: .leading)
+        }
+        .buttonStyle(BannerButtonStyle())
+    }
+}
+
+private struct BannerButtonStyle: ButtonStyle {
+    @Environment(\.theme) private var theme
+    
+    let bannerShape = RoundedRectangle(cornerRadius: 8)
+    
+    func makeBody(configuration: Configuration) -> some View {
+        configuration.label
+            .padding(12)
+            .shapedBorder(color: theme.colors.quarterlyContent, borderWidth: 1.5, shape: bannerShape)
+            .background(configuration.isPressed ? theme.colors.system : theme.colors.background, in: bannerShape)
+            .contentShape(bannerShape)
+    }
+}
+
+struct SunsetDownloadBanner_Previews: PreviewProvider {
+    static var previews: some View {
+        SunsetDownloadBanner(replacementApp: BuildSettings.replacementApp!) { }
+            .padding(.horizontal)
+    }
+}
diff --git a/RiotSwiftUI/Modules/Common/Sunset/SunsetOIDCRegistrationBanner.swift b/RiotSwiftUI/Modules/Common/Sunset/SunsetOIDCRegistrationBanner.swift
new file mode 100644
index 0000000000..aff81d3db5
--- /dev/null
+++ b/RiotSwiftUI/Modules/Common/Sunset/SunsetOIDCRegistrationBanner.swift
@@ -0,0 +1,52 @@
+// 
+// Copyright 2025 New Vector Ltd
+//
+// SPDX-License-Identifier: AGPL-3.0-only
+// Please see LICENSE in the repository root for full details.
+//
+
+import SwiftUI
+
+struct SunsetOIDCRegistrationBanner: View {
+    @Environment(\.theme) private var theme
+    
+    let homeserverAddress: String
+    let replacementApp: BuildSettings.ReplacementApp
+    
+    private let bannerShape = RoundedRectangle(cornerRadius: 8)
+    
+    var body: some View {
+        VStack(alignment: .leading, spacing: 4) {
+            Label {
+                Text(VectorL10n.sunsetDelegatedOidcRegistrationNotSupportedTitle(homeserverAddress))
+            } icon: {
+                Image(systemName: "exclamationmark.circle.fill")
+            }
+            .font(theme.fonts.callout.bold())
+            .foregroundStyle(theme.colors.alert)
+            
+            Label {
+                Text(VectorL10n.sunsetDelegatedOidcRegistrationNotSupportedMessage(replacementApp.name, homeserverAddress))
+                    .font(theme.fonts.footnote)
+            } icon: {
+                // Invisible Icon to align the Text with the one above.
+                Image(systemName: "circle")
+                    .font(theme.fonts.callout.bold())
+                    .hidden()
+            }
+            .foregroundStyle(theme.colors.primaryContent)
+        }
+        .frame(maxWidth: .infinity, alignment: .leading)
+        .padding(12)
+        .background(theme.colors.alert.opacity(0.05), in: bannerShape)
+        .shapedBorder(color: theme.colors.alert.opacity(0.5), borderWidth: 2, shape: bannerShape)
+    }
+}
+
+struct SunsetRegistrationAlert_Previews: PreviewProvider {
+    static var previews: some View {
+        SunsetOIDCRegistrationBanner(homeserverAddress: "beta.matrix.org",
+                                replacementApp: BuildSettings.replacementApp!)
+            .padding(.horizontal)
+    }
+}
diff --git a/changelog.d/7889.api b/changelog.d/7889.api
new file mode 100644
index 0000000000..8caf0115fa
--- /dev/null
+++ b/changelog.d/7889.api
@@ -0,0 +1 @@
+Adds a BuildSettings.replacementApp setting, used to control the sunset banners.
\ No newline at end of file
diff --git a/changelog.d/7889.change b/changelog.d/7889.change
new file mode 100644
index 0000000000..d5ebf11b1e
--- /dev/null
+++ b/changelog.d/7889.change
@@ -0,0 +1 @@
+Show sunset banners, guiding users to install Element X when registering a new account against a server with MAS.
\ No newline at end of file