diff --git a/Package.resolved b/Package.resolved
index 6d120da..191a4f2 100644
--- a/Package.resolved
+++ b/Package.resolved
@@ -1,6 +1,15 @@
 {
   "object": {
     "pins": [
+      {
+        "package": "NordicDFU",
+        "repositoryURL": "https://github.com/NordicSemiconductor/IOS-DFU-Library",
+        "state": {
+          "branch": null,
+          "revision": "f73213f2de57c8c53700725ee2cff6cd35ef66fe",
+          "version": "4.11.1"
+        }
+      },
       {
         "package": "swift-collections",
         "repositoryURL": "https://github.com/apple/swift-collections",
@@ -9,6 +18,15 @@
           "revision": "48254824bb4248676bf7ce56014ff57b142b77eb",
           "version": "1.0.2"
         }
+      },
+      {
+        "package": "ZIPFoundation",
+        "repositoryURL": "https://github.com/weichsel/ZIPFoundation",
+        "state": {
+          "branch": null,
+          "revision": "ec32d62d412578542c0ffb7a6ce34d3e64b43b94",
+          "version": "0.9.11"
+        }
       }
     ]
   },
diff --git a/Package.swift b/Package.swift
index 068ae41..1456723 100644
--- a/Package.swift
+++ b/Package.swift
@@ -14,7 +14,8 @@ let package = Package(
     ],
     dependencies: [
         // Dependencies declare other packages that this package depends on.
-        .package(url: "https://github.com/apple/swift-collections", "1.0.0"..<"2.0.0")
+        .package(url: "https://github.com/apple/swift-collections", "1.0.0"..<"2.0.0"),
+        .package(url: "https://github.com/NordicSemiconductor/IOS-DFU-Library", .upToNextMajor(from: "4.11.1"))
     ],
     targets: [
         // Targets are the basic building blocks of a package. A target can define a module or a test suite.
@@ -22,7 +23,8 @@ let package = Package(
         .target(
             name: "CombustionBLE",
             dependencies: [
-                .product(name: "Collections", package: "swift-collections", condition: nil)
+                .product(name: "Collections", package: "swift-collections"),
+                .product(name: "NordicDFU", package: "IOS-DFU-Library")
             ],
             path: "Sources/CombustionBLE"),
         /*
diff --git a/Sources/CombustionBLE/BleManager.swift b/Sources/CombustionBLE/BleManager.swift
index 0f2ff91..2985565 100644
--- a/Sources/CombustionBLE/BleManager.swift
+++ b/Sources/CombustionBLE/BleManager.swift
@@ -27,6 +27,8 @@ SOFTWARE.
 
 import Foundation
 import CoreBluetooth
+import NordicDFU
+
 
 protocol BleManagerDelegate: AnyObject {
     func didConnectTo(identifier: UUID)
@@ -34,7 +36,7 @@ protocol BleManagerDelegate: AnyObject {
     func didDisconnectFrom(identifier: UUID)
     func handleSetIDResponse(identifier: UUID, success: Bool)
     func handleSetColorResponse(identifier: UUID, success: Bool)
-    func updateDeviceWithAdvertising(advertising: AdvertisingData, rssi: NSNumber, identifier: UUID)
+    func updateDeviceWithAdvertising(advertising: AdvertisingData, isConnectable: Bool, rssi: NSNumber, identifier: UUID)
     func updateDeviceWithLogResponse(identifier: UUID, logResponse: LogResponse)
     func updateDeviceWithSessionInformation(identifier: UUID, sessionInformation: SessionInformation)
     func updateDeviceWithStatus(identifier: UUID, status: DeviceStatus)
@@ -87,6 +89,18 @@ class BleManager : NSObject {
         }
     }
     
+    func startFirmwareUpdate(device: Device, dfu: DFUFirmware) {
+        if let connectionPeripheral = getConnectedPeripheral(identifier: device.identifier) {
+            let initiator = DFUServiceInitiator().with(firmware: dfu)
+
+            initiator.delegate = device
+            initiator.progressDelegate = device
+
+
+            initiator.start(target: connectionPeripheral)
+        }
+    }
+    
     private func getConnectedPeripheral(identifier: String) -> CBPeripheral? {
         let uuid = UUID(uuidString: identifier)
         let devicePeripherals = peripherals.filter { $0.identifier == uuid }
@@ -123,6 +137,7 @@ extension BleManager: CBCentralManagerDelegate{
                                advertisementData: [String : Any], rssi RSSI: NSNumber) {
         
         let manufatureData: Data = advertisementData[CBAdvertisementDataManufacturerDataKey] as? Data ?? Data()
+        let isConnectable = advertisementData[CBAdvertisementDataIsConnectable] as? Bool ?? false
 
         if let advData = AdvertisingData(fromData: manufatureData) {
             // For now, only add probes.
@@ -131,7 +146,10 @@ extension BleManager: CBCentralManagerDelegate{
                 // Store peripheral reference for later use
                 peripherals.insert(peripheral)
 
-                delegate?.updateDeviceWithAdvertising(advertising: advData, rssi: RSSI, identifier: peripheral.identifier)
+                delegate?.updateDeviceWithAdvertising(advertising: advData,
+                                                      isConnectable: isConnectable,
+                                                      rssi: RSSI,
+                                                      identifier: peripheral.identifier)
             } else {
                 // print("Ignoring device with type \(advData.type)")
             }
@@ -288,5 +306,4 @@ extension BleManager: CBPeripheralDelegate {
             }
         }
     }
-    
 }
diff --git a/Sources/CombustionBLE/Device.swift b/Sources/CombustionBLE/Device.swift
index 4c1d0dd..c0f10c3 100644
--- a/Sources/CombustionBLE/Device.swift
+++ b/Sources/CombustionBLE/Device.swift
@@ -26,6 +26,7 @@ SOFTWARE.
 --*/
 
 import Foundation
+import NordicDFU
 
 /// Struct containing info about a thermometer device.
 public class Device : ObservableObject {
@@ -54,6 +55,9 @@ public class Device : ObservableObject {
     /// Current connection state of device
     @Published public internal(set) var connectionState: ConnectionState = .disconnected
     
+    /// Connectable flag set in advertising packet
+    @Published public internal(set) var isConnectable = false
+    
     /// Signal strength to device
     @Published public internal(set) var rssi: Int
     
@@ -63,6 +67,26 @@ public class Device : ObservableObject {
     /// Tracks whether the data has gone stale (no new data in some time)
     @Published public internal(set) var stale = false
     
+    /// DFU state
+    @Published public private(set) var dfuState: DFUState?
+    
+    public struct DFUErrorMessage {
+        public let error: DFUError
+        public let message: String
+    }
+    
+    /// DFU error message
+    @Published public private(set) var dfuError: DFUErrorMessage?
+
+    public struct DFUUploadProgress {
+        public let part: Int
+        public let totalParts: Int
+        public let progress: Int
+    }
+    
+    /// DFU Upload progress
+    @Published public private(set) var dfuUploadProgress: DFUUploadProgress?
+    
     /// Time at which device was last updated
     internal var lastUpdateTime = Date()
     
@@ -82,6 +106,22 @@ public class Device : ObservableObject {
     
     func updateDeviceStale() {
         stale = Date().timeIntervalSince(lastUpdateTime) > Constants.STALE_TIMEOUT
+        
+        
+        // If device data is stale, assume its not longer connectable
+        if(stale) {
+            isConnectable = false
+        }
+    }
+    
+    public func isDFURunning() -> Bool {
+        guard let dfuState = dfuState else { return false }
+        
+        if(dfuState == .completed) {
+            return false
+        }
+        
+        return true
     }
 }
     
@@ -95,7 +135,6 @@ extension Device {
     /// Attempt to connect to the device.
     public func connect() {
         // Mark that we should maintain a connection to this device.
-        // TODO - this doesn't seem to be propagating back to the UI??
         maintainingConnection = true
         
         if(connectionState != .connected) {
@@ -123,3 +162,23 @@ extension Device: Hashable {
         hasher.combine(identifier)
     }
 }
+
+extension Device: DFUServiceDelegate {
+    public func dfuStateDidChange(to state: DFUState) {
+        dfuState = state
+    }
+    
+    public func dfuError(_ error: DFUError, didOccurWithMessage message: String) {
+        dfuError = DFUErrorMessage(error: error, message: message)
+    }
+}
+
+extension Device: DFUProgressDelegate {
+    public func dfuProgressDidChange(for part: Int,
+                                     outOf totalParts: Int,
+                                     to progress: Int,
+                                     currentSpeedBytesPerSecond: Double,
+                                     avgSpeedBytesPerSecond: Double) {
+        dfuUploadProgress = DFUUploadProgress(part: part, totalParts: totalParts, progress: progress)
+    }
+}
diff --git a/Sources/CombustionBLE/DeviceManager.swift b/Sources/CombustionBLE/DeviceManager.swift
index c14d75d..fc51ef5 100644
--- a/Sources/CombustionBLE/DeviceManager.swift
+++ b/Sources/CombustionBLE/DeviceManager.swift
@@ -26,7 +26,7 @@ SOFTWARE.
 
 import Foundation
 import SwiftUI
-
+import NordicDFU
 
 /// Singleton that provides list of detected Devices
 /// (either via Bluetooth or from a list in the Cloud)
@@ -162,11 +162,22 @@ public class DeviceManager : ObservableObject {
     /// - parameter ProbeColor: New Probe color
     public func setProbeColor(_ device: Device, color: ProbeColor, completionHandler: @escaping (Bool) -> Void) {
         setColorCompetionHandlers[device.identifier] = MessageHandler(timeSent: Date(), handler: completionHandler)
-        
+
         let request = SetColorRequest(color: color)
         BleManager.shared.sendRequest(identifier: device.identifier, request: request)
     }
     
+    public func runSoftwareUpgrade(_ device: Device, otaFile: URL) -> Bool {
+        do {
+            let dfu = try DFUFirmware(urlToZipFile: otaFile)
+            BleManager.shared.startFirmwareUpdate(device: device, dfu: dfu)
+            return true
+        }
+        catch {
+            return false
+        }
+    }
+    
     private func checkForMessageTimeout(messageHandlers: inout [String: MessageHandler]) {
         let currentTime = Date()
         
@@ -225,14 +236,14 @@ extension DeviceManager : BleManagerDelegate {
         }
     }
     
-    func updateDeviceWithAdvertising(advertising: AdvertisingData, rssi: NSNumber, identifier: UUID) {
+    func updateDeviceWithAdvertising(advertising: AdvertisingData, isConnectable: Bool, rssi: NSNumber, identifier: UUID) {
         if devices[identifier.uuidString] != nil {
             if let probe = devices[identifier.uuidString] as? Probe {
-                probe.updateWithAdvertising(advertising, RSSI: rssi)
+                probe.updateWithAdvertising(advertising, isConnectable: isConnectable, RSSI: rssi)
             }
         }
         else {
-            let device = Probe(advertising, RSSI: rssi, identifier: identifier)
+            let device = Probe(advertising, isConnectable: isConnectable, RSSI: rssi, identifier: identifier)
             addDevice(device: device)
         }
     }
diff --git a/Sources/CombustionBLE/Probe.swift b/Sources/CombustionBLE/Probe.swift
index 2c7b06b..6908dfc 100644
--- a/Sources/CombustionBLE/Probe.swift
+++ b/Sources/CombustionBLE/Probe.swift
@@ -70,14 +70,14 @@ public class Probe : Device {
     /// Time at which probe instant read was last updated
     internal var lastInstantRead: Date?
     
-    public init(_ advertising: AdvertisingData, RSSI: NSNumber, identifier: UUID) {
+    public init(_ advertising: AdvertisingData, isConnectable: Bool, RSSI: NSNumber, identifier: UUID) {
         serialNumber = advertising.serialNumber
         id = advertising.id
         color = advertising.color
         
         super.init(identifier: identifier, RSSI: RSSI)
         
-        updateWithAdvertising(advertising, RSSI: RSSI)
+        updateWithAdvertising(advertising, isConnectable: isConnectable, RSSI: RSSI)
     }
     
     override func updateConnectionState(_ state: ConnectionState) {
@@ -108,21 +108,29 @@ extension Probe {
     }
     
     
-    func updateWithAdvertising(_ advertising: AdvertisingData, RSSI: NSNumber) {
-        if(advertising.mode == .Normal) {
-            currentTemperatures = advertising.temperatures
-        }
-        else if(advertising.mode == .InstantRead ){
-            updateInstantRead(advertising.temperatures.values[0])
-        }
+    func updateWithAdvertising(_ advertising: AdvertisingData, isConnectable: Bool, RSSI: NSNumber) {
+        // Always update probe RSSI and isConnectable flag
+        self.rssi = RSSI.intValue
+        self.isConnectable = isConnectable
         
-        rssi = RSSI.intValue
-        
-        id = advertising.id
-        color = advertising.color
-        batteryStatus = advertising.batteryStatus
-        
-        lastUpdateTime = Date()
+        // Only update rest of data if not connected to probe.  Otherwise, rely on status
+        // notifications to update data
+        if(connectionState != .connected)
+        {
+            if(advertising.mode == .Normal) {
+                currentTemperatures = advertising.temperatures
+            }
+            else if(advertising.mode == .InstantRead ){
+                updateInstantRead(advertising.temperatures.values[0])
+            }
+            
+
+            id = advertising.id
+            color = advertising.color
+            batteryStatus = advertising.batteryStatus
+            
+            lastUpdateTime = Date()
+        }
     }
     
     /// Updates the Device based on newly-received DeviceStatus message. Requests missing records.
diff --git a/Sources/CombustionBLE/SimulatedProbe.swift b/Sources/CombustionBLE/SimulatedProbe.swift
index f58e012..810e877 100644
--- a/Sources/CombustionBLE/SimulatedProbe.swift
+++ b/Sources/CombustionBLE/SimulatedProbe.swift
@@ -31,7 +31,7 @@ class SimulatedProbe: Probe {
     init() {
         let advertising = AdvertisingData(fakeSerial: UInt32.random(in: 0 ..< UINT32_MAX),
                                           fakeTemperatures: ProbeTemperatures.withRandomData())
-        super.init(advertising, RSSI: SimulatedProbe.randomeRSSI(), identifier: UUID())
+        super.init(advertising, isConnectable: true, RSSI: SimulatedProbe.randomeRSSI(), identifier: UUID())
         
         firmareVersion = "v1.2.3"
         hardwareRevision = "v0.31-A1"
@@ -64,7 +64,7 @@ class SimulatedProbe: Probe {
     private func updateFakeAdvertising() {
         let advertising = AdvertisingData(fakeSerial: UInt32.random(in: 0 ..< UINT32_MAX),
                                           fakeTemperatures: ProbeTemperatures.withRandomData())
-        updateWithAdvertising(advertising, RSSI: SimulatedProbe.randomeRSSI())
+        updateWithAdvertising(advertising, isConnectable: true, RSSI: SimulatedProbe.randomeRSSI())
     }
     
     private func updateFakeStatus() {
diff --git a/Sources/CombustionBLE/UART/LogRequest.swift b/Sources/CombustionBLE/UART/LogRequest.swift
index b8e2f50..b77cec1 100644
--- a/Sources/CombustionBLE/UART/LogRequest.swift
+++ b/Sources/CombustionBLE/UART/LogRequest.swift
@@ -27,23 +27,15 @@ SOFTWARE.
 import Foundation
 
 class LogRequest: Request {
-    static let PAYLOAD_LENGTH: UInt8 = 8
-    
     init(minSequence: UInt32, maxSequence: UInt32) {
-        super.init(payloadLength: LogRequest.PAYLOAD_LENGTH, type: .Log)
+        var payload = Data()
         
         var min = minSequence
-        let minData = Data(bytes: &min, count: MemoryLayout.size(ofValue: min))
-        self.data[Request.HEADER_SIZE + 0] = minData[0]
-        self.data[Request.HEADER_SIZE + 1] = minData[1]
-        self.data[Request.HEADER_SIZE + 2] = minData[2]
-        self.data[Request.HEADER_SIZE + 3] = minData[3]
+        payload.append(Data(bytes: &min, count: MemoryLayout.size(ofValue: min)))
         
         var max = maxSequence
-        let maxData = Data(bytes: &max, count: MemoryLayout.size(ofValue: max))
-        self.data[Request.HEADER_SIZE + 4] = maxData[0]
-        self.data[Request.HEADER_SIZE + 5] = maxData[1]
-        self.data[Request.HEADER_SIZE + 6] = maxData[2]
-        self.data[Request.HEADER_SIZE + 7] = maxData[3]
+        payload.append(Data(bytes: &max, count: MemoryLayout.size(ofValue: max)))
+        
+        super.init(payload: payload, type: .Log)
     }
 }
diff --git a/Sources/CombustionBLE/UART/LogResponse.swift b/Sources/CombustionBLE/UART/LogResponse.swift
index f7eea11..f88fe98 100644
--- a/Sources/CombustionBLE/UART/LogResponse.swift
+++ b/Sources/CombustionBLE/UART/LogResponse.swift
@@ -33,7 +33,7 @@ class LogResponse: Response {
     let sequenceNumber: UInt32
     let temperatures: ProbeTemperatures
     
-    init(data: Data, success: Bool) {
+    init(data: Data, success: Bool, payloadLength: Int) {
         let sequenceByteIndex = Response.HEADER_LENGTH
         let sequenceRaw = data.subdata(in: sequenceByteIndex..<(sequenceByteIndex + 4))
         sequenceNumber = sequenceRaw.withUnsafeBytes {
@@ -47,6 +47,17 @@ class LogResponse: Response {
         // print("******** Received response!")
         // print("Sequence = \(sequenceNumber) : Temperature = \(temperatures)")
 
-        super.init(success: success, payLoadLength: LogResponse.PAYLOAD_LENGTH)
+        super.init(success: success, payLoadLength: payloadLength)
+    }
+}
+
+extension LogResponse {
+
+    static func fromRaw(data: Data, success: Bool, payloadLength: Int) -> LogResponse? {
+        if(payloadLength < PAYLOAD_LENGTH) {
+            return nil
+        }
+            
+        return LogResponse(data: data, success: success, payloadLength: payloadLength)
     }
 }
diff --git a/Sources/CombustionBLE/UART/Request.swift b/Sources/CombustionBLE/UART/Request.swift
index 9e0636a..faf3a9f 100644
--- a/Sources/CombustionBLE/UART/Request.swift
+++ b/Sources/CombustionBLE/UART/Request.swift
@@ -32,25 +32,35 @@ class Request {
     static let HEADER_SIZE = 6
     
     /// Contains message data.
-    var data: Data
+    var data = Data()
     
     /// Constructor for Request object.
     /// - parameter payloadLength: Length of payload of message
     /// - parameter type: Type of message
-    init(payloadLength: UInt8, type: MessageType) {
-        let messageSize = Request.HEADER_SIZE + Int(payloadLength)
-        data = Data(repeating: 0, count: messageSize)
+    init(payload: Data, type: MessageType) {
         
         // Sync Bytes { 0xCA, 0xFE }
-        data[0] = 0xCA
-        data[1] = 0xFE
+        data.append(0xCA)
+        data.append(0xFE)
         
-        // CRC : TODO
+        // Calculate CRC over Message Type, payload length, payload
+        var crcData = Data()
         
         // Message type
-        data[4] = type.rawValue
+        crcData.append(type.rawValue)
         
         // Payload length
-        data[5] = payloadLength
+        crcData.append(UInt8(payload.count))
+        
+        // Payload
+        crcData.append(payload)
+        
+        var crcValue = crcData.crc16ccitt()
+        
+        // CRC
+        data.append(Data(bytes: &crcValue, count: MemoryLayout.size(ofValue: crcValue)))
+        
+        // Message Type, payload length, payload
+        data.append(crcData)
     }
 }
diff --git a/Sources/CombustionBLE/UART/Response.swift b/Sources/CombustionBLE/UART/Response.swift
index 1769590..aa404f5 100644
--- a/Sources/CombustionBLE/UART/Response.swift
+++ b/Sources/CombustionBLE/UART/Response.swift
@@ -68,8 +68,6 @@ extension Response {
             return nil
         }
         
-        // CRC : TODO (bytes 2,3)
-        
         // Message type
         let typeByte = data.subdata(in: 4..<5)
         let typeRaw = typeByte.withUnsafeBytes {
@@ -93,6 +91,23 @@ extension Response {
             $0.load(as: UInt8.self)
         }
         
+        // CRC
+        let crcBytes = data.subdata(in: 2..<4)
+        let crc = crcBytes.withUnsafeBytes {
+            $0.load(as: UInt16.self)
+        }
+        
+        let crcDataLength = 3 + Int(payloadLength)
+        var crcData = data.dropFirst(4)
+        crcData = crcData.dropLast(crcData.count - crcDataLength)
+        
+        let calculatedCRC = crcData.crc16ccitt()
+        
+        guard crc == calculatedCRC else {
+            print("Response::fromData(): Invalid CRC")
+            return nil
+        }
+        
         let responseLength = Int(payloadLength) + HEADER_LENGTH
         
         // Invalid number of bytes
@@ -104,13 +119,13 @@ extension Response {
         
         switch messageType {
         case .Log:
-            return LogResponse(data: data, success: success)
+            return LogResponse.fromRaw(data: data, success: success, payloadLength: Int(payloadLength))
         case .SetID:
             return SetIDResponse(success: success, payLoadLength: Int(payloadLength))
         case .SetColor:
             return SetColorResponse(success: success, payLoadLength: Int(payloadLength))
         case .SessionInfo:
-            return SessionInfoResponse(data: data, success: success)
+            return SessionInfoResponse.fromRaw(data: data, success: success, payloadLength: Int(payloadLength))
         }
     }
 }
diff --git a/Sources/CombustionBLE/UART/SessionInfo.swift b/Sources/CombustionBLE/UART/SessionInfo.swift
index a565c61..d82eb82 100644
--- a/Sources/CombustionBLE/UART/SessionInfo.swift
+++ b/Sources/CombustionBLE/UART/SessionInfo.swift
@@ -32,10 +32,8 @@ public struct SessionInformation {
 }
 
 class SessionInfoRequest: Request {
-    static let PAYLOAD_LENGTH: UInt8 = 0
-    
     init() {
-        super.init(payloadLength: SessionInfoRequest.PAYLOAD_LENGTH, type: .SessionInfo)
+        super.init(payload: Data(), type: .SessionInfo)
     }
 }
 
@@ -44,7 +42,7 @@ class SessionInfoResponse: Response {
     
     let info: SessionInformation
     
-    init(data: Data, success: Bool) {
+    init(data: Data, success: Bool, payloadLength: Int) {
         let sequenceByteIndex = Response.HEADER_LENGTH
         let sessionIDRaw = data.subdata(in: sequenceByteIndex..<(sequenceByteIndex + 4))
         let sessionID = sessionIDRaw.withUnsafeBytes {
@@ -58,6 +56,17 @@ class SessionInfoResponse: Response {
         
         info = SessionInformation(sessionID: sessionID, samplePeriod: samplePeriod)
 
-        super.init(success: success, payLoadLength: SessionInfoResponse.PAYLOAD_LENGTH)
+        super.init(success: success, payLoadLength: payloadLength)
+    }
+}
+
+extension SessionInfoResponse {
+
+    static func fromRaw(data: Data, success: Bool, payloadLength: Int) -> SessionInfoResponse? {
+        if(payloadLength < PAYLOAD_LENGTH) {
+            return nil
+        }
+            
+        return SessionInfoResponse(data: data, success: success, payloadLength: payloadLength)
     }
 }
diff --git a/Sources/CombustionBLE/UART/SetColor.swift b/Sources/CombustionBLE/UART/SetColor.swift
index 8736099..411e71c 100644
--- a/Sources/CombustionBLE/UART/SetColor.swift
+++ b/Sources/CombustionBLE/UART/SetColor.swift
@@ -27,11 +27,11 @@ SOFTWARE.
 import Foundation
 
 class SetColorRequest: Request {
-    static let PAYLOAD_LENGTH: UInt8 = 1
-    
     init(color: ProbeColor) {
-        super.init(payloadLength: SetColorRequest.PAYLOAD_LENGTH, type: .SetColor)
-        self.data[Request.HEADER_SIZE] = color.rawValue
+        var payload = Data()
+        payload.append(color.rawValue)
+        
+        super.init(payload: payload, type: .SetColor)
     }
 }
 
diff --git a/Sources/CombustionBLE/UART/SetID.swift b/Sources/CombustionBLE/UART/SetID.swift
index be56a89..0717a1e 100644
--- a/Sources/CombustionBLE/UART/SetID.swift
+++ b/Sources/CombustionBLE/UART/SetID.swift
@@ -27,11 +27,11 @@ SOFTWARE.
 import Foundation
 
 class SetIDRequest: Request {
-    static let PAYLOAD_LENGTH: UInt8 = 1
-    
     init(id: ProbeID) {
-        super.init(payloadLength: SetIDRequest.PAYLOAD_LENGTH, type: .SetID)
-        self.data[Request.HEADER_SIZE] = id.rawValue
+        var payload = Data()
+        payload.append(id.rawValue)
+        
+        super.init(payload: payload, type: .SetID)
     }
 }
 
diff --git a/Sources/CombustionBLE/Utilities/CSV.swift b/Sources/CombustionBLE/Utilities/CSV.swift
index 474bb4f..979e4ef 100644
--- a/Sources/CombustionBLE/Utilities/CSV.swift
+++ b/Sources/CombustionBLE/Utilities/CSV.swift
@@ -38,12 +38,14 @@ public struct CSV {
         let dateString = dateFormatter.string(from: date)
         
         output.append("Combustion Inc. Probe Data")
-        output.append("iOS app: \(appVersion)")
-        output.append("CSV version: 2")
+        output.append("App: iOS \(appVersion)")
+        output.append("CSV version: 3")
         output.append("Probe S/N: \(String(format: "%4X", probe.serialNumber))")
         output.append("Probe FW version: \(probe.firmareVersion ?? "??")")
         output.append("Probe HW revision: \(probe.hardwareRevision ?? "??")")
-        output.append("\(dateString)")
+        output.append("Framework: iOS")
+        output.append("Sample Period: \(probe.temperatureLogs.first?.sessionInformation.samplePeriod ?? 0)")
+        output.append("Created: \(dateString)")
         output.append("")
         
         // Header
@@ -55,20 +57,20 @@ public struct CSV {
                 for dataPoint in session.dataPoints {
                     
                     // Calculate timestamp for current data point
-                    var timeStamp = 0
+                    var timeStamp: TimeInterval = 0
                     if let currentSessionStart = session.startTime?.timeIntervalSince1970 {
                         // Number of seconds between first session start time and current start time
-                        let sessionStartTimeDiff = Int(currentSessionStart - firstSessionStart)
+                        let sessionStartTimeDiff = currentSessionStart - firstSessionStart
                         
                         // Number of seconds beteen current data point and session start time
-                        let dataPointSeconds = Int(dataPoint.sequenceNum) * Int(session.sessionInformation.samplePeriod) / 1000
+                        let dataPointSeconds = Double(dataPoint.sequenceNum) * Double(session.sessionInformation.samplePeriod) / 1000.0
                         
                         // Number of seconds between current data point and first session start
                         timeStamp = dataPointSeconds + sessionStartTimeDiff
                     }
 
                     
-                    output.append(String(format: "%d,%u,%d,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f",
+                    output.append(String(format: "%.3f,%u,%d,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f,%.2f",
                                          timeStamp,
                                          session.id,
                                          dataPoint.sequenceNum,
diff --git a/Sources/CombustionBLE/Utilities/Data+CRC.swift b/Sources/CombustionBLE/Utilities/Data+CRC.swift
new file mode 100644
index 0000000..8caaa51
--- /dev/null
+++ b/Sources/CombustionBLE/Utilities/Data+CRC.swift
@@ -0,0 +1,46 @@
+//  Data+CRC.swift
+
+/*--
+MIT License
+
+Copyright (c) 2022 Combustion Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+--*/
+
+import Foundation
+
+extension Data {
+    func crc16ccitt() -> UInt16 {
+        var crc: UInt16 = 0xFFFF // initial value
+        let polynomial: UInt16 = 0x1021 // 0001 0000 0010 0001  (0, 5, 12)
+
+        self.forEach { (byte) in
+            for i in 0...7 {
+                let bit = (byte >> (7 - i) & 1) == 1
+                let c15 = (crc  >> (15)    & 1) == 1
+                crc = crc << 1
+                if (c15 != bit) {
+                    crc = crc ^ polynomial
+                }
+            }
+        }
+        return crc & 0xffff
+    }
+}