diff --git a/NucleicRemote/NucleicRemote.xcodeproj/project.pbxproj b/NucleicRemote/NucleicRemote.xcodeproj/project.pbxproj
index 48ce307..dcd9688 100644
--- a/NucleicRemote/NucleicRemote.xcodeproj/project.pbxproj
+++ b/NucleicRemote/NucleicRemote.xcodeproj/project.pbxproj
@@ -136,6 +136,7 @@
 				BP00000000000000000003 /* Frameworks */,
 				BP00000000000000000004 /* Resources */,
 				BP00000000000000000005 /* Embed Foundation Extensions */,
+				BP00000000000000000009 /* Stamp git commit into Info.plist */,
 			);
 			buildRules = (
 			);
@@ -235,6 +236,24 @@
 		};
 /* End PBXResourcesBuildPhase section */
 
+/* Begin PBXShellScriptBuildPhase section */
+		BP00000000000000000009 /* Stamp git commit into Info.plist */ = {
+			isa = PBXShellScriptBuildPhase;
+			alwaysOutOfDate = 1;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+			);
+			name = "Stamp git commit into Info.plist";
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "# Stamp the short git commit into the built Info.plist (NucleicCommit key), the iOS\n# mirror of the Mac's EmbedGitCommit prebuild plugin. Runs before code signing so the\n# signature covers the stamped value; alwaysOutOfDate keeps it fresh on every build. A\n# trailing \"+\" marks a dirty tree; \"unknown\" (no git) makes the app fall back to the\n# bundle build number.\nset -e\nplist=\"${TARGET_BUILD_DIR}/${INFOPLIST_PATH}\"\n[ -f \"$plist\" ] || exit 0\nhash=$(git -C \"${SRCROOT}\" rev-parse --short HEAD 2>/dev/null || echo unknown)\nif [ \"$hash\" != unknown ] && [ -n \"$(git -C \"${SRCROOT}\" status --porcelain 2>/dev/null)\" ]; then\n  hash=\"${hash}+\"\nfi\n/usr/libexec/PlistBuddy -c \"Set :NucleicCommit $hash\" \"$plist\" 2>/dev/null || /usr/libexec/PlistBuddy -c \"Add :NucleicCommit string $hash\" \"$plist\"\n";
+		};
+/* End PBXShellScriptBuildPhase section */
+
 /* Begin PBXSourcesBuildPhase section */
 		BP00000000000000000002 /* Sources */ = {
 			isa = PBXSourcesBuildPhase;
@@ -305,6 +324,9 @@
 				CURRENT_PROJECT_VERSION = 1;
 				DEVELOPMENT_TEAM = L7UDTQ6F5W;
 				ENABLE_PREVIEWS = YES;
+				// The "Stamp git commit into Info.plist" phase shells out to git and rewrites the
+				// built Info.plist, both of which script sandboxing would block.
+				ENABLE_USER_SCRIPT_SANDBOXING = NO;
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_FILE = NucleicRemote/Info.plist;
 				INFOPLIST_KEY_CFBundleDisplayName = "Nucleic$(NUCLEIC_NAME_SUFFIX)";
@@ -349,6 +371,9 @@
 				CURRENT_PROJECT_VERSION = 1;
 				DEVELOPMENT_TEAM = L7UDTQ6F5W;
 				ENABLE_PREVIEWS = YES;
+				// The "Stamp git commit into Info.plist" phase shells out to git and rewrites the
+				// built Info.plist, both of which script sandboxing would block.
+				ENABLE_USER_SCRIPT_SANDBOXING = NO;
 				GENERATE_INFOPLIST_FILE = YES;
 				INFOPLIST_FILE = NucleicRemote/Info.plist;
 				INFOPLIST_KEY_CFBundleDisplayName = "Nucleic$(NUCLEIC_NAME_SUFFIX)";
diff --git a/NucleicRemote/NucleicRemote/Info.plist b/NucleicRemote/NucleicRemote/Info.plist
index bb77515..6b1a38f 100644
--- a/NucleicRemote/NucleicRemote/Info.plist
+++ b/NucleicRemote/NucleicRemote/Info.plist
@@ -8,6 +8,11 @@
 	</array>
 	<key>NucleicChannel</key>
 	<string>$(NUCLEIC_CHANNEL)</string>
+	<!-- The short git commit this build came from, shown in the non-release banner to match
+	     the Mac. Left empty here and overwritten in the built product by the NucleicRemote
+	     target's "Stamp git commit into Info.plist" build phase (git rev-parse --short HEAD). -->
+	<key>NucleicCommit</key>
+	<string></string>
 	<key>NSSupportsLiveActivities</key>
 	<true/>
 	<!-- Export compliance: the app ships a Noise-Protocol secure channel (X25519 /
diff --git a/NucleicRemote/NucleicRemote/Models/RemoteStore.swift b/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
index 40b4dc7..329099f 100644
--- a/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
+++ b/NucleicRemote/NucleicRemote/Models/RemoteStore.swift
@@ -293,7 +293,8 @@ final class RemoteStore: ObservableObject {
         let client = SyncClient(
             channel: channel, identity: identity, hostStaticKey: payload.hostStaticKey,
             mode: .pair(secret: payload.pairingSecret), deviceID: deviceID,
-            deviceLabel: UIDevice.current.name, pushToken: PushRegistrar.shared.tokenHex)
+            deviceLabel: UIDevice.current.name, pushToken: PushRegistrar.shared.tokenHex,
+            releaseChannel: BuildInfo.current.channel.releaseChannel)
         self.client = client
         consume(client, pairingPayload: payload)
     }
@@ -312,7 +313,8 @@ final class RemoteStore: ObservableObject {
         let client = SyncClient(
             channel: channel, identity: identity, hostStaticKey: host.hostStaticKey,
             mode: .reconnect, deviceID: host.deviceID, deviceLabel: UIDevice.current.name,
-            pushToken: PushRegistrar.shared.tokenHex)
+            pushToken: PushRegistrar.shared.tokenHex,
+            releaseChannel: BuildInfo.current.channel.releaseChannel)
         self.client = client
         consume(client, pairingPayload: nil)
     }
@@ -781,6 +783,15 @@ final class RemoteStore: ObservableObject {
             openDiff = diff
             diffLoading = false
         case .wireError(let error):
+            // A channel mismatch means the host and this remote were built from incompatible
+            // release channels. Surface it as a persistent failure with a clear message rather
+            // than a transient bubble; the follow-on `.closed` still schedules a backoff retry,
+            // so the connection recovers on its own once either side is updated to a matching
+            // channel.
+            if error.code == .channelMismatch {
+                connectivity = .failed(error.message)
+                break
+            }
             // Not fatal — surface as a transient bubble (the Mac's last-error overlay).
             // Losing an approval race isn't an error worth interrupting for; the card
             // collapses on the matching `approvalResolved`.
diff --git a/NucleicRemote/NucleicRemote/Views/BuildBanner.swift b/NucleicRemote/NucleicRemote/Views/BuildBanner.swift
index e2b9f79..b062025 100644
--- a/NucleicRemote/NucleicRemote/Views/BuildBanner.swift
+++ b/NucleicRemote/NucleicRemote/Views/BuildBanner.swift
@@ -1,4 +1,5 @@
 import SwiftUI
+import NucleicProtocol
 
 /// How this copy of the remote was built — the iOS mirror of the Mac's `BuildChannel`.
 /// Stamped at archive time via the `NucleicChannel` Info.plist key (`$(NUCLEIC_CHANNEL)`,
@@ -16,14 +17,31 @@ enum BuildChannel {
     case releaseCandidate
     /// The `stable` channel — no banner.
     case release
+
+    /// The wire projection sent to the host in `hello`, so it can gate the connection on
+    /// channel compatibility (`ReleaseChannel.isCompatible`).
+    var releaseChannel: ReleaseChannel {
+        switch self {
+        case .local: .local
+        case .canary: .canary
+        case .beta: .beta
+        case .releaseCandidate: .releaseCandidate
+        case .release: .release
+        }
+    }
 }
 
 /// Build identity for the running app: which channel it came from and its build label.
-/// The Mac embeds a git commit via a prebuild plugin; the iOS build number is derived from
-/// `git rev-list --count` at archive time (scripts/ios-release.sh), so `CFBundleVersion`
-/// plays the same role here.
+/// Both platforms show the short git commit: the Mac embeds it via a prebuild plugin, and
+/// here the NucleicRemote target's "Stamp git commit into Info.plist" build phase writes
+/// `git rev-parse --short HEAD` into the `NucleicCommit` Info.plist key. Falls back to
+/// `CFBundleVersion` (the `git rev-list --count` build number from scripts/ios-release.sh)
+/// when git isn't available.
 struct BuildInfo {
     let channel: BuildChannel
+    /// The short git commit the binary was built from (e.g. "a1b2c3d", "+" suffix when the
+    /// tree was dirty) — matching the Mac's banner. Falls back to `CFBundleVersion` / "local"
+    /// if the build phase couldn't resolve a hash.
     let buildLabel: String
     /// `CFBundleShortVersionString` when present, else `nil`.
     let version: String?
@@ -34,7 +52,13 @@ struct BuildInfo {
     init() {
         let info = Bundle.main.infoDictionary
         version = info?["CFBundleShortVersionString"] as? String
-        buildLabel = (info?["CFBundleVersion"] as? String) ?? "local"
+        // Prefer the stamped git commit (mirrors the Mac's GitCommit.hash); an empty or
+        // "unknown" value means git wasn't available at build time, so fall back to the
+        // bundle build number.
+        let commit = info?["NucleicCommit"] as? String
+        buildLabel = commit.flatMap { $0.isEmpty || $0 == "unknown" ? nil : $0 }
+            ?? (info?["CFBundleVersion"] as? String)
+            ?? "local"
         channel = Self.detectChannel(stamped: info?["NucleicChannel"] as? String)
     }
 
@@ -111,7 +135,7 @@ struct BuildBanner: View {
             case .canary:
                 tint = Color(red: 1.00, green: 0.87, blue: 0.00)   // bright canary yellow
                 label = "Canary Build"
-                icon = "bird.fill"
+                icon = "bell.and.waves.left.and.right.fill"
             case .beta:
                 tint = Color(red: 0.13, green: 0.40, blue: 0.86)   // blue
                 label = "Engineering Beta"
@@ -127,7 +151,7 @@ struct BuildBanner: View {
 
         func tooltip(version: String?, build: String) -> String {
             let v = version.map { "\($0) " } ?? ""
-            return "\(label) — \(v)build \(build). Not a release build."
+            return "\(label) — \(v)commit \(build). Not a release build."
         }
     }
 }