LoopKit · ps2 · Dec 31, 2025 · Dec 31, 2025 · Jan 1, 2026 · Jan 1, 2026
diff --git a/G7SensorKit.xcodeproj/project.pbxproj b/G7SensorKit.xcodeproj/project.pbxproj
@@ -11,6 +11,8 @@
 		B60BB2E42BC649DA00D2BB39 /* Bundle.swift in Sources */ = {isa = PBXBuildFile; fileRef = B60BB2E32BC649DA00D2BB39 /* Bundle.swift */; };
 		B66D1F6D2E6A803800471149 /* Localizable.xcstrings in Resources */ = {isa = PBXBuildFile; fileRef = B66D1F6C2E6A803800471149 /* Localizable.xcstrings */; };
 		B66D1F6F2E6A803800471149 /* Localizable.xcstrings in Resources */ = {isa = PBXBuildFile; fileRef = B66D1F6E2E6A803800471149 /* Localizable.xcstrings */; };
+		C107607F2F059130008B2B39 /* ExtendedVersionMessage.swift in Sources */ = {isa = PBXBuildFile; fileRef = C107607E2F05912B008B2B39 /* ExtendedVersionMessage.swift */; };
+		C10760812F05B41B008B2B39 /* ExtendedVersionMessageTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C10760802F05B412008B2B39 /* ExtendedVersionMessageTests.swift */; };
 		C109F14A291ECCE2008EA5B6 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = C109F149291ECCE2008EA5B6 /* Assets.xcassets */; };
 		C109F14C291ED66F008EA5B6 /* G7GlucoseMessageTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = C109F14B291ED66F008EA5B6 /* G7GlucoseMessageTests.swift */; };
 		C139829829295D7D0047DB5F /* HKUnit.swift in Sources */ = {isa = PBXBuildFile; fileRef = C17F514A291EB6F000555EB5 /* HKUnit.swift */; };
@@ -112,6 +114,8 @@
 		B60BB2E32BC649DA00D2BB39 /* Bundle.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = Bundle.swift; path = G7SensorKitUI/Extensions/Bundle.swift; sourceTree = SOURCE_ROOT; };
 		B66D1F6C2E6A803800471149 /* Localizable.xcstrings */ = {isa = PBXFileReference; lastKnownFileType = text.json.xcstrings; path = Localizable.xcstrings; sourceTree = "<group>"; };
 		B66D1F6E2E6A803800471149 /* Localizable.xcstrings */ = {isa = PBXFileReference; lastKnownFileType = text.json.xcstrings; path = Localizable.xcstrings; sourceTree = "<group>"; };
+		C107607E2F05912B008B2B39 /* ExtendedVersionMessage.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ExtendedVersionMessage.swift; sourceTree = "<group>"; };
+		C10760802F05B412008B2B39 /* ExtendedVersionMessageTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ExtendedVersionMessageTests.swift; sourceTree = "<group>"; };
 		C109F149291ECCE2008EA5B6 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		C109F14B291ED66F008EA5B6 /* G7GlucoseMessageTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = G7GlucoseMessageTests.swift; sourceTree = "<group>"; };
 		C1409A08291EC22F006BE8D0 /* OSLog.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OSLog.swift; sourceTree = "<group>"; };
@@ -240,6 +244,7 @@
 		C17F50D2291EAC3800555EB5 /* G7SensorKitTests */ = {
 			isa = PBXGroup;
 			children = (
+				C10760802F05B412008B2B39 /* ExtendedVersionMessageTests.swift */,
 				C17F50D3291EAC3800555EB5 /* G7SensorKitTests.swift */,
 				C109F14B291ED66F008EA5B6 /* G7GlucoseMessageTests.swift */,
 			);
@@ -319,6 +324,7 @@
 		C17F5141291EB34800555EB5 /* Messages */ = {
 			isa = PBXGroup;
 			children = (
+				C107607E2F05912B008B2B39 /* ExtendedVersionMessage.swift */,
 				C17F50E3291EAC6500555EB5 /* G7Opcode.swift */,
 				C17F5146291EB57700555EB5 /* SensorMessage.swift */,
 				C17F50E8291EAC6500555EB5 /* G7GlucoseMessage.swift */,
@@ -571,6 +577,7 @@
 				C17F5140291EB27D00555EB5 /* TimeInterval.swift in Sources */,
 				C17F50F0291EAC6500555EB5 /* G7CGMManagerState.swift in Sources */,
 				C17F5145291EB45900555EB5 /* CBPeripheral.swift in Sources */,
+				C107607F2F059130008B2B39 /* ExtendedVersionMessage.swift in Sources */,
 				C17F513A291EB0D900555EB5 /* GlucoseLimits.swift in Sources */,
 				C17F5143291EB36700555EB5 /* AuthChallengeRxMessage.swift in Sources */,
 				C17F50EA291EAC6500555EB5 /* G7DeviceStatus.swift in Sources */,
@@ -595,6 +602,7 @@
 			buildActionMask = 2147483647;
 			files = (
 				C109F14C291ED66F008EA5B6 /* G7GlucoseMessageTests.swift in Sources */,
+				C10760812F05B41B008B2B39 /* ExtendedVersionMessageTests.swift in Sources */,
 				C17F50D4291EAC3800555EB5 /* G7SensorKitTests.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

diff --git a/G7SensorKit/G7CGMManager/G7CGMManager.swift b/G7SensorKit/G7CGMManager/G7CGMManager.swift
@@ -112,26 +112,42 @@ public class G7CGMManager: CGMManager {
         return state.activatedAt
     }
 
+    public var lifetime: TimeInterval {
+        if let sessionLength = state.extendedVersion?.sessionDuration {
+            return sessionLength - gracePeriod
+        } else {
+            return G7Sensor.defaultLifetime
+        }
+    }
+
+    public var warmupDuration: TimeInterval {
+        state.extendedVersion?.warmupDuration ?? G7Sensor.defaultWarmupDuration
+    }
+
+    public var gracePeriod: TimeInterval {
+        state.extendedVersion?.gracePeriodDuration ?? G7Sensor.defaultGracePeriod
+    }
+
     public var sensorExpiresAt: Date? {
         guard let activatedAt = sensorActivatedAt else {
             return nil
         }
-        return activatedAt.addingTimeInterval(G7Sensor.lifetime)
+        return activatedAt.addingTimeInterval(lifetime)
     }
 
     public var sensorEndsAt: Date? {
         guard let activatedAt = sensorActivatedAt else {
             return nil
         }
-        return activatedAt.addingTimeInterval(G7Sensor.lifetime + G7Sensor.gracePeriod)
+        return activatedAt.addingTimeInterval(lifetime + gracePeriod)
     }
 
 
     public var sensorFinishesWarmupAt: Date? {
         guard let activatedAt = sensorActivatedAt else {
             return nil
         }
-        return activatedAt.addingTimeInterval(G7Sensor.warmupDuration)
+        return activatedAt.addingTimeInterval(warmupDuration)
     }
 
     public var latestReading: G7GlucoseMessage? {
@@ -201,6 +217,7 @@ public class G7CGMManager: CGMManager {
         lockedState = Locked(state)
         sensor = G7Sensor(sensorID: state.sensorID)
         sensor.delegate = self
+        sensor.needsVersionInfo = state.extendedVersion == nil
     }
 
     public var rawState: RawStateValue {
@@ -243,6 +260,7 @@ public class G7CGMManager: CGMManager {
         mutateState { state in
             state.sensorID = nil
             state.activatedAt = nil
+            state.extendedVersion = nil
         }
         sensor.scanForNewSensor()
     }
@@ -298,8 +316,8 @@ extension G7CGMManager: G7SensorDelegate {
                 date: activatedAt,
                 type: .sensorStart,
                 deviceIdentifier: name,
-                expectedLifetime: .hours(24 * 10 + 12),
-                warmupPeriod: .hours(2)
+                expectedLifetime: lifetime + gracePeriod,
+                warmupPeriod: warmupDuration
             )
             delegate.notify { delegate in
                 delegate?.cgmManager(self, hasNew: [event])
@@ -309,6 +327,12 @@ extension G7CGMManager: G7SensorDelegate {
         return shouldSwitchToNewSensor
     }
 
+    public func sensor(_ sensor: G7Sensor, didReceive extendedVersion: ExtendedVersionMessage) {
+        mutateState { state in
+            state.extendedVersion = extendedVersion
+        }
+    }
+
     public func sensorDidConnect(_ sensor: G7Sensor, name: String) {
         mutateState { state in
             state.latestConnect = Date()

diff --git a/G7SensorKit/G7CGMManager/G7CGMManagerState.swift b/G7SensorKit/G7CGMManager/G7CGMManagerState.swift
@@ -15,6 +15,7 @@ public struct G7CGMManagerState: RawRepresentable, Equatable {
 
     public var sensorID: String?
     public var activatedAt: Date?
+    public var extendedVersion: ExtendedVersionMessage?
     public var latestReading: G7GlucoseMessage?
     public var latestReadingTimestamp: Date?
     public var latestConnect: Date?
@@ -29,6 +30,9 @@ public struct G7CGMManagerState: RawRepresentable, Equatable {
         if let readingData = rawValue["latestReading"] as? Data {
             latestReading = G7GlucoseMessage(data: readingData)
         }
+        if let extendedVersionData = rawValue["extendedVersion"] as? Data {
+            extendedVersion = ExtendedVersionMessage(data: extendedVersionData)
+        }
         self.latestReadingTimestamp = rawValue["latestReadingTimestamp"] as? Date
         self.latestConnect = rawValue["latestConnect"] as? Date
         self.uploadReadings = rawValue["uploadReadings"] as? Bool ?? false
@@ -39,6 +43,7 @@ public struct G7CGMManagerState: RawRepresentable, Equatable {
         rawValue["sensorID"] = sensorID
         rawValue["activatedAt"] = activatedAt
         rawValue["latestReading"] = latestReading?.data
+        rawValue["extendedVersion"] = extendedVersion?.data
         rawValue["latestReadingTimestamp"] = latestReadingTimestamp
         rawValue["latestConnect"] = latestConnect
         rawValue["uploadReadings"] = uploadReadings

diff --git a/G7SensorKit/G7CGMManager/G7PeripheralManager.swift b/G7SensorKit/G7CGMManager/G7PeripheralManager.swift
@@ -80,6 +80,20 @@ class G7PeripheralManager: NSObject {
 
         assertConfiguration()
     }
+
+    func requestExtendedVersion() throws {
+        self.log.default("Requesting sensor extended version");
+        guard let service = peripheral.services?.itemWithUUID(SensorServiceUUID.cgmService.cbUUID) else {
+            self.log.error("Peripheral missing cgm service. Services = %{public}@", String(describing: peripheral.services));
+            throw PeripheralManagerError.invalidConfiguration
+        }
+
+        guard let characteristic = service.characteristics?.itemWithUUID(CGMServiceCharacteristicUUID.control.cbUUID) else {
+            throw PeripheralManagerError.unknownCharacteristic
+        }
+
+        try writeValue(Data([G7Opcode.extendedVersionTx.rawValue]), for: characteristic, type: .withResponse, timeout: 1)
+    }
 }
 
 

diff --git a/G7SensorKit/G7CGMManager/G7Sensor.swift b/G7SensorKit/G7CGMManager/G7Sensor.swift
@@ -28,6 +28,8 @@ public protocol G7SensorDelegate: AnyObject {
     // If this returns true, then start following this sensor
     func sensor(_ sensor: G7Sensor, didDiscoverNewSensor name: String, activatedAt: Date) -> Bool
 
+    func sensor(_ sensor: G7Sensor, didReceive extendedVersion: ExtendedVersionMessage)
+
     // This is triggered for connection/disconnection events, and enabling/disabling scan
     func sensorConnectionStatusDidUpdate(_ sensor: G7Sensor)
 }
@@ -62,9 +64,9 @@ public enum G7SensorLifecycleState {
 
 
 public final class G7Sensor: G7BluetoothManagerDelegate {
-    public static let lifetime = TimeInterval(hours: 10 * 24)
-    public static let warmupDuration = TimeInterval(minutes: 25)
-    public static let gracePeriod = TimeInterval(hours: 12)
+    public static let defaultLifetime = TimeInterval(hours: 10 * 24)
+    public static let defaultWarmupDuration = TimeInterval(minutes: 27)
+    public static let defaultGracePeriod = TimeInterval(hours: 12)
 
     public weak var delegate: G7SensorDelegate?
 
@@ -73,6 +75,9 @@ public final class G7Sensor: G7BluetoothManagerDelegate {
     /// The initial activation date of the sensor
     var activationDate: Date?
 
+    /// The initial activation date of the sensor
+    var needsVersionInfo: Bool = false
+
     /// The date of last connection
     private var lastConnection: Date?
 
@@ -92,10 +97,6 @@ public final class G7Sensor: G7BluetoothManagerDelegate {
 
     private var sensorID: String?
 
-    public func setSensorId(_ newId: String) {
-        self.sensorID = newId
-    }
-
     public init(sensorID: String?) {
         self.sensorID = sensorID
         bluetoothManager.delegate = self
@@ -138,6 +139,17 @@ public final class G7Sensor: G7BluetoothManagerDelegate {
                 }
             }
         }
+
+        if needsVersionInfo, let name = peripheralManager.peripheral.name, name == sensorID {
+            peripheralManager.perform { (peripheral) in
+                do {
+                    try peripheral.requestExtendedVersion()
+                } catch let error {
+                    self.log.error("Error trying to request extended version: %{public}@", String(describing: error))
+                }
+            }
+        }
+
         if sensorID == nil, let name = peripheralManager.peripheral.name, let activationDate = activationDate  {
             delegateQueue.async {
                 guard let delegate = self.delegate else {
@@ -147,8 +159,18 @@ public final class G7Sensor: G7BluetoothManagerDelegate {
                 if delegate.sensor(self, didDiscoverNewSensor: name, activatedAt: activationDate) {
                     self.sensorID = name
                     self.activationDate = activationDate
+                    self.needsVersionInfo = true
                     self.delegate?.sensor(self, didRead: message)
                     self.bluetoothManager.stopScanning()
+                    if self.needsVersionInfo, let name = peripheralManager.peripheral.name, name == self.sensorID {
+                        peripheralManager.perform { (peripheral) in
+                            do {
+                                try peripheral.requestExtendedVersion()
+                            } catch let error {
+                                self.log.error("Error trying to request extended version on initial detection: %{public}@", String(describing: error))
+                            }
+                        }
+                    }
                 }
             }
         } else if sensorID != nil {
@@ -251,6 +273,14 @@ public final class G7Sensor: G7BluetoothManagerDelegate {
                     self.delegate?.sensor(self, didError: G7SensorError.observationError("Unable to handle glucose control response"))
                 }
             }
+        case .extendedVersionTx:
+            if let extendedVersionMessage = ExtendedVersionMessage(data: response) {
+                log.default("Received %{public}@", String(describing: extendedVersionMessage))
+                delegateQueue.async {
+                    self.delegate?.sensor(self, didReceive: extendedVersionMessage)
+                    self.needsVersionInfo = false
+                }
+            }
         case .backfillFinished:
             flushBackfillBuffer()
         default:

diff --git a/G7SensorKit/Messages/ExtendedVersionMessage.swift b/G7SensorKit/Messages/ExtendedVersionMessage.swift
@@ -0,0 +1,46 @@
+//
+//  ExtendedVersion.swift
+//  G7SensorKit
+//
+//  Created by Pete Schwamb on 12/31/25.
+//  Copyright © 2025 LoopKit Authors. All rights reserved.
+//
+
+import Foundation
+import LoopKit
+
+public struct ExtendedVersionMessage: SensorMessage, Equatable {
+    public let sessionDuration: TimeInterval
+    public let warmupDuration: TimeInterval
+    public let algorithmVersion: UInt32
+    public let hardwareVersion: UInt8
+    public let gracePeriodDuration: TimeInterval
+
+    public let data: Data
+
+    init?(data: Data) {
+        self.data = data
+
+        // 52 00 c0d70d00 5406 00020404 ff 0c00
+
+        guard data.starts(with: .extendedVersionTx) else {
+            return nil
+        }
+
+        guard data.count >= 15 else {
+            return nil
+        }
+
+        sessionDuration = TimeInterval(data[2..<6].to(UInt32.self))
+        warmupDuration = TimeInterval(data[6..<8].to(UInt16.self))
+        algorithmVersion = data[8..<12].to(UInt32.self)
+        hardwareVersion = data[12]
+        gracePeriodDuration = TimeInterval(hours: Double(data[13..<15].to(UInt16.self)))
+    }
+}
+
+extension ExtendedVersionMessage: CustomDebugStringConvertible {
+    public var debugDescription: String {
+        return "ExtendedVersionMessage(sessionDuration:\(sessionDuration), warmupDuration:\(warmupDuration) algorithmVersion:\(algorithmVersion) hardwareVersion:\(hardwareVersion) gracePeriodDuration:\(gracePeriodDuration))"
+    }
+}
diff --git a/G7SensorKit/Messages/G7Opcode.swift b/G7SensorKit/Messages/G7Opcode.swift
@@ -12,5 +12,7 @@ enum G7Opcode: UInt8 {
     case authChallengeRx = 0x05
     case sessionStopTx = 0x28
     case glucoseTx = 0x4e
+    case extendedVersionTx = 0x52
+    case extendedVersionRx = 0x53
     case backfillFinished = 0x59
 }
diff --git a/G7SensorKitTests/ExtendedVersionMessageTests.swift b/G7SensorKitTests/ExtendedVersionMessageTests.swift
@@ -0,0 +1,24 @@
+//
+//  ExtendedVersionMessageTests.swift
+//  G7SensorKit
+//
+//  Created by Pete Schwamb on 12/31/25.
+//  Copyright © 2025 LoopKit Authors. All rights reserved.
+//
+
+import XCTest
+@testable import G7SensorKit
+
+final class ExtendedVersionMessageTests: XCTestCase {
+
+    func testBasicMessage() {
+        let data = Data(hexadecimalString: "5200c0d70d00540600020404ff0c00")!
+        let message = ExtendedVersionMessage(data: data)!
+
+        XCTAssertEqual(10.5, message.sessionDuration.hours / 24)
+        XCTAssertEqual(27, message.warmupDuration.minutes)
+        XCTAssertEqual(67371520, message.algorithmVersion)
+        XCTAssertEqual(255, message.hardwareVersion)
+        XCTAssertEqual(12, message.gracePeriodDuration.hours)
+    }
+}
diff --git a/G7SensorKitUI/G7CGMManager/G7CGMManager+UI.swift b/G7SensorKitUI/G7CGMManager/G7CGMManager+UI.swift
@@ -109,15 +109,15 @@ extension G7CGMManager: CGMManagerUI {
             let remaining = max(0, expiration.timeIntervalSinceNow)
 
             if remaining < .hours(24) {
-                return G7LifecycleProgress(percentComplete: 1-(remaining/G7Sensor.lifetime), progressState: .warning)
+                return G7LifecycleProgress(percentComplete: 1-(remaining/lifetime), progressState: .warning)
             }
             return nil
         case .gracePeriod:
             guard let endTime = sensorEndsAt else {
                 return nil
             }
             let remaining = max(0, endTime.timeIntervalSinceNow)
-            return G7LifecycleProgress(percentComplete: 1-(remaining/G7Sensor.gracePeriod), progressState: .critical)
+            return G7LifecycleProgress(percentComplete: 1-(remaining/gracePeriod), progressState: .critical)
         case .expired:
             return G7LifecycleProgress(percentComplete: 1, progressState: .critical)
         default:

diff --git a/G7SensorKitUI/Views/G7SettingsView.swift b/G7SensorKitUI/Views/G7SettingsView.swift
@@ -65,13 +65,13 @@ struct G7SettingsView: View {
                 HStack {
                     Text(LocalizedString("Sensor Expiration", comment: "title for g7 settings row showing sensor expiration time"))
                     Spacer()
-                    Text(timeFormatter.string(from: activatedAt.addingTimeInterval(G7Sensor.lifetime)))
+                    Text(timeFormatter.string(from: activatedAt.addingTimeInterval(viewModel.lifetime)))
                         .foregroundColor(.secondary)
                 }
                 HStack {
                     Text(LocalizedString("Grace Period End", comment: "title for g7 settings row showing sensor grace period end time"))
                     Spacer()
-                    Text(timeFormatter.string(from: activatedAt.addingTimeInterval(G7Sensor.lifetime + G7Sensor.gracePeriod)))
+                    Text(timeFormatter.string(from: activatedAt.addingTimeInterval(viewModel.lifetime + viewModel.gracePeriod)))
                         .foregroundColor(.secondary)
                 }
             }