diff --git a/Memory/ARCHITECTURE.md b/Memory/ARCHITECTURE.md
index e67b605e..17b19c4f 100644
--- a/Memory/ARCHITECTURE.md
+++ b/Memory/ARCHITECTURE.md
@@ -697,7 +697,8 @@ remain. Metrics uses vertical labeled-icon menu or horizontal principal segmente
 coexist. iOS 27 uses `ToolbarOverflowMenu`, older OS labeled menus. Save stays labeled with form progress. Native
 minimized SSH/SFTP search stays in every placement; sidebar/pose changes never activate search or claim focus.
 
-On iOS 27.1 content reads active division/occlusion ReservedRegions after safe-area/keyboard layout. Frames include
+When built with the iOS 27.1 SDK, iOS 27.1 content reads active division/occlusion ReservedRegions after
+safe-area/keyboard layout. Frames include
 margins and follow SwiftUI's leading-origin convention, including RTL. Terminal/shortcuts/notices occupy the largest
 continuous unobstructed rectangle, ties top then leading. Ghostty resizes the existing PTY and rejects invalid
 viewports; session ownership survives pose. Assistant keeps one transcript and one scrollable interaction surface
diff --git a/TFI/DesignSystem/MobileContentRegions.swift b/TFI/DesignSystem/MobileContentRegions.swift
index d80fbe52..04f39f71 100644
--- a/TFI/DesignSystem/MobileContentRegions.swift
+++ b/TFI/DesignSystem/MobileContentRegions.swift
@@ -122,15 +122,17 @@ struct MobileRegionReader<Content: View>: View {
 
     private func regions(in geometry: GeometryProxy) -> [MobileReservedRegion] {
         if let override { return override }
-        if #available(iOS 27.1, *) {
-            // The default mirrored query matches Layout placement in both LTR and RTL.
-            return geometry.reservedRegions(kind: .division).map {
-                MobileReservedRegion(kind: .division, frame: $0.frame, isActive: $0.isActive)
-            }
-                + geometry.reservedRegions(kind: .occlusion).map {
-                    MobileReservedRegion(kind: .occlusion, frame: $0.frame, isActive: $0.isActive)
+        #if TERMIND_HAS_IOS_27_1_SDK
+            if #available(iOS 27.1, *) {
+                // The default mirrored query matches Layout placement in both LTR and RTL.
+                return geometry.reservedRegions(kind: .division).map {
+                    MobileReservedRegion(kind: .division, frame: $0.frame, isActive: $0.isActive)
                 }
-        }
+                    + geometry.reservedRegions(kind: .occlusion).map {
+                        MobileReservedRegion(kind: .occlusion, frame: $0.frame, isActive: $0.isActive)
+                    }
+            }
+        #endif
         return []
     }
 }
diff --git a/TFI/DesignSystem/MobileToolbarEnvironment.swift b/TFI/DesignSystem/MobileToolbarEnvironment.swift
index ef16fc5b..19f15224 100644
--- a/TFI/DesignSystem/MobileToolbarEnvironment.swift
+++ b/TFI/DesignSystem/MobileToolbarEnvironment.swift
@@ -18,27 +18,35 @@ private struct MobileToolbarEnvironment: ViewModifier {
     @Environment(\.tabBarPlacement) private var placement
 
     func body(content: Content) -> some View {
-        if #available(iOS 27.1, *) {
-            content.modifier(MobileVerticalToolbarEnvironment(isTopBar: placement == .topBar))
-        } else {
+        #if TERMIND_HAS_IOS_27_1_SDK
+            if #available(iOS 27.1, *) {
+                content.modifier(MobileVerticalToolbarEnvironment(isTopBar: placement == .topBar))
+            } else {
+                content.environment(
+                    \.mobileToolbarLayout,
+                    MobileToolbarLayout(isTopBar: placement == .topBar))
+            }
+        #else
             content.environment(
                 \.mobileToolbarLayout,
                 MobileToolbarLayout(isTopBar: placement == .topBar))
+        #endif
+    }
+}
+
+#if TERMIND_HAS_IOS_27_1_SDK
+    @available(iOS 27.1, *)
+    private struct MobileVerticalToolbarEnvironment: ViewModifier {
+        let isTopBar: Bool
+        @Environment(\.toolbarVerticalEdge) private var edge
+
+        func body(content: Content) -> some View {
+            content.environment(
+                \.mobileToolbarLayout,
+                MobileToolbarLayout(isTopBar: isTopBar, verticalEdge: edge))
         }
     }
-}
-
-@available(iOS 27.1, *)
-private struct MobileVerticalToolbarEnvironment: ViewModifier {
-    let isTopBar: Bool
-    @Environment(\.toolbarVerticalEdge) private var edge
-
-    func body(content: Content) -> some View {
-        content.environment(
-            \.mobileToolbarLayout,
-            MobileToolbarLayout(isTopBar: isTopBar, verticalEdge: edge))
-    }
-}
+#endif
 
 extension View {
     func mobileToolbarEnvironment() -> some View {
diff --git a/Termind.xcodeproj/project.pbxproj b/Termind.xcodeproj/project.pbxproj
index 73b75b7c..ca295d4e 100644
--- a/Termind.xcodeproj/project.pbxproj
+++ b/Termind.xcodeproj/project.pbxproj
@@ -1786,7 +1786,7 @@
 				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
 				CODE_SIGN_ENTITLEMENTS = TFI/TFI.entitlements;
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 24;
+				CURRENT_PROJECT_VERSION = 25;
 				GENERATE_INFOPLIST_FILE = YES;
 				ICLOUD_CONTAINER_ENVIRONMENT = Development;
 				INFOPLIST_FILE = TFI/Info.plist;
@@ -2059,7 +2059,7 @@
 				ASSETCATALOG_COMPILER_GLOBAL_ACCENT_COLOR_NAME = AccentColor;
 				CODE_SIGN_ENTITLEMENTS = TFI/TFI.entitlements;
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 24;
+				CURRENT_PROJECT_VERSION = 25;
 				GENERATE_INFOPLIST_FILE = YES;
 				ICLOUD_CONTAINER_ENVIRONMENT = Production;
 				INFOPLIST_FILE = TFI/Info.plist;
@@ -2220,6 +2220,8 @@
 				ONLY_ACTIVE_ARCH = YES;
 				STRING_CATALOG_GENERATE_SYMBOLS = YES;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = "DEBUG $(inherited)";
+				"SWIFT_ACTIVE_COMPILATION_CONDITIONS[sdk=iphoneos27.1*]" = "$(inherited) TERMIND_HAS_IOS_27_1_SDK";
+				"SWIFT_ACTIVE_COMPILATION_CONDITIONS[sdk=iphonesimulator27.1*]" = "$(inherited) TERMIND_HAS_IOS_27_1_SDK";
 				SWIFT_APPROACHABLE_CONCURRENCY = YES;
 				SWIFT_DEFAULT_ACTOR_ISOLATION = MainActor;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
@@ -2277,6 +2279,8 @@
 				MTL_ENABLE_DEBUG_INFO = NO;
 				MTL_FAST_MATH = YES;
 				STRING_CATALOG_GENERATE_SYMBOLS = YES;
+				"SWIFT_ACTIVE_COMPILATION_CONDITIONS[sdk=iphoneos27.1*]" = "$(inherited) TERMIND_HAS_IOS_27_1_SDK";
+				"SWIFT_ACTIVE_COMPILATION_CONDITIONS[sdk=iphonesimulator27.1*]" = "$(inherited) TERMIND_HAS_IOS_27_1_SDK";
 				SWIFT_APPROACHABLE_CONCURRENCY = YES;
 				SWIFT_COMPILATION_MODE = wholemodule;
 				SWIFT_DEFAULT_ACTOR_ISOLATION = MainActor;
@@ -2298,7 +2302,7 @@
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
 				COMBINE_HIDPI_IMAGES = YES;
-				CURRENT_PROJECT_VERSION = 31;
+				CURRENT_PROJECT_VERSION = 32;
 				DEAD_CODE_STRIPPING = YES;
 				DEVELOPMENT_ASSET_PATHS = "";
 				ENABLE_APP_SANDBOX = YES;
@@ -2335,7 +2339,7 @@
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
 				COMBINE_HIDPI_IMAGES = YES;
-				CURRENT_PROJECT_VERSION = 31;
+				CURRENT_PROJECT_VERSION = 32;
 				DEAD_CODE_STRIPPING = YES;
 				DEVELOPMENT_ASSET_PATHS = "";
 				ENABLE_APP_SANDBOX = YES;