diff --git a/README.md b/README.md
index 9aaf847..6478c93 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,8 @@ The FIT JavaScript SDK uses ECMAScript module syntax and requires Node.js v14.0
 ```sh
 npm install @garmin/fitsdk
 ```
-## Usage
+## Decoder
+### Usage
 ````js
 import { Decoder, Stream, Profile, Utils } from '@garmin/fitsdk';
 
@@ -27,8 +28,6 @@ const { messages, errors } = decoder.read();
 console.log(errors);
 console.log(messages);
 ````
-## Decoder
-
 ### Constructor
 
 Decoder objects are created from Streams representing the binary FIT file data to be decoded. See [Creating Streams](#creatingstreams) for more information on constructing Stream objects.
@@ -37,16 +36,16 @@ Once a Decoder object is created it can be used to check that the Stream is a FI
 
 ### isFIT Method
 
-All valid FIT files should include a 12 or 14 byte file header. The 14 byte header is the preferred header size and the most common size used. Bytes 8–11 of the header contain the ASCII values ".FIT”. This string can easily be spotted when opening a binary FIT file in a text or hex editor.
+All valid FIT files should include a 12 or 14 byte file header. The 14 byte header is the preferred header size and the most common size used. Bytes 8–11 of the header contain the ASCII values ".FIT". This string can easily be spotted when opening a binary FIT file in a text or hex editor.
 
-```
+````bash
   Offset: 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
 00000000: 0E 10 43 08 78 06 09 00 2E 46 49 54 96 85 40 00    ..C.x....FIT..@.
 00000010: 00 00 00 07 03 04 8C 04 04 86 07 04 86 01 02 84    ................
 00000020: 02 02 84 05 02 84 00 01 00 00 19 28 7E C5 95 B0    ...........(~E.0
-```
+````
 
-The isFIT method reads the file header and returns true if bytes 8–11 are equal to the ACSII values ".FIT”. isFIT provides a quick way to check that the file is a FIT file before attempting to decode the file.
+The isFIT method reads the file header and returns true if bytes 8–11 are equal to the ACSII values ".FIT". isFIT provides a quick way to check that the file is a FIT file before attempting to decode the file.
 
 The Decoder class includes a static and instance version of the isFIT method.
 
@@ -54,7 +53,7 @@ The Decoder class includes a static and instance version of the isFIT method.
 
 The checkIntegrity method performs three checks on a FIT file:
 
-1. Checks that bytes 8–11 of the header contain the ASCII values ".FIT”.
+1. Checks that bytes 8–11 of the header contain the ASCII values ".FIT".
 2. Checks that the total file size is equal to Header Size + Data Size + CRC Size.
 3. Reads the contents of the file, computes the CRC, and then checks that the computed CRC matches the file CRC.
 
@@ -83,7 +82,6 @@ const { messages, errors } = decoder.read({
 Optional callback function that can be used to inspect or manipulate messages after they are fully decoded and all the options have been applied. The message is mutable and we be returned from the Read method in the messages dictionary.
 
 Example mesgListener callback that tracks the field names across all Record messages.
-
 ````js
 const recordFields = new Set();
 
@@ -221,3 +219,65 @@ A convince method for converting FIT Epoch values to JavaScript Date objects.
 ````js
 const jsDate = Utils.convertDateTimeToDate(fitDateTime);
 ````
+## Encoder
+### Usage
+````js 
+// Import the SDK
+import { Encoder, Profile} from "@garmin/fitsdk";
+
+// Create an Encoder
+const encoder = new Encoder();
+
+//
+// Write messages to the output-stream
+//
+// The message data should match the format returned by
+// the Decoder. Field names should be camelCase. The fields 
+// definitions can be found in the Profile.
+//
+
+// Pass the MesgNum and message data as separate parameters to the onMesg() method
+encoder.onMesg(Profile.MesgNum.FILE_ID, {
+  manufacturer: "development",
+  product: 1,
+  timeCreated: new Date(),
+  type: "activity",
+});
+
+// The writeMesg() method expects the mesgNum to be included in the message data
+// Internally, writeMesg() calls onMesg()
+encoder.writeMesg({
+  mesgNum: Profile.MesgNum.FILE_ID,
+  manufacturer: "development",
+  product: 1,
+  timeCreated: new Date(),
+  type: "activity",
+});
+
+// Unknown values in the message will be ignored by the Encoder
+encoder.onMesg(Profile.MesgNum.FILE_ID, {
+  manufacturer: "development",
+  product: 1,
+  timeCreated: new Date(),
+  type: "activity",
+  customField: 12345, // This value will be ignored by the Encoder
+});
+
+// Subfield values in the message will be ignored by the Encoder
+encoder.onMesg(Profile.MesgNum.FILE_ID, {
+  manufacturer: "development",
+  product: 4440, // This is the main product field, which is a uint16
+  garminProduct: "edge1050", // This value will be ignored by the Encoder, use the main field value instead
+  timeCreated: new Date(),
+  type: "activity",
+});
+
+// Closing the encoder returns the file as an UInt8 Array
+const uint8Array = encoder.close();
+
+// Write the file to disk,
+import * as fs from "fs";
+fs.writeFileSync("example.fit", uint8Array);
+       
+````
+See the [Encode Activity Recipe](https://github.com/garmin/fit-javascript-sdk/blob/main/test/encode-activity-recipe.test.js) for a complete example of encoding a FIT Activity file usine the FIT JavaScript SDK.
diff --git a/package.json b/package.json
index fb40cfe..a426760 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@garmin/fitsdk",
-  "version": "21.170.0",
+  "version": "21.171.0",
   "description": "FIT JavaScript SDK",
   "main": "src/index.js",
   "type": "module",
diff --git a/src/accumulator.js b/src/accumulator.js
index fbadad6..0268cd7 100644
--- a/src/accumulator.js
+++ b/src/accumulator.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/bit-stream.js b/src/bit-stream.js
index b9e22c3..d9b8ca4 100644
--- a/src/bit-stream.js
+++ b/src/bit-stream.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/crc-calculator.js b/src/crc-calculator.js
index 5472fdd..818bd6b 100644
--- a/src/crc-calculator.js
+++ b/src/crc-calculator.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/decoder.js b/src/decoder.js
index 89305d3..c57c470 100644
--- a/src/decoder.js
+++ b/src/decoder.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/encoder.js b/src/encoder.js
index 2d18fce..c7e5d3f 100644
--- a/src/encoder.js
+++ b/src/encoder.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/fit.js b/src/fit.js
index 16bd3e9..62fbbba 100644
--- a/src/fit.js
+++ b/src/fit.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/index.js b/src/index.js
index 800670f..91737dc 100644
--- a/src/index.js
+++ b/src/index.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/mesg-definition.js b/src/mesg-definition.js
index 3e1c474..492406b 100644
--- a/src/mesg-definition.js
+++ b/src/mesg-definition.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/output-stream.js b/src/output-stream.js
index fb42536..992f38c 100644
--- a/src/output-stream.js
+++ b/src/output-stream.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/profile.js b/src/profile.js
index 03226ca..4a52091 100644
--- a/src/profile.js
+++ b/src/profile.js
@@ -5,15 +5,15 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
 const Profile = {
     version: {
         major: 21,
-        minor: 170,
+        minor: 171,
         patch: 0,
         type: "Release"
     },
@@ -24716,6 +24716,8 @@ types: {
        4586: "instinct3Amoled45mm",
        4587: "instinct3Amoled50mm",
        4588: "descentG2",
+       4606: "hrm200",
+       4625: "vivoactive6",
        4647: "approachS44",
        4656: "approachS50",
        4666: "fenixE",
@@ -24843,6 +24845,8 @@ types: {
        4: "drill",
        5: "mixed",
        6: "im", // IM is a mixed interval containing the same number of lengths for each of: Butterfly, Backstroke, Breaststroke, Freestyle, swam in that order.
+       7: "imByRound", // For repeated workout steps, a new individual medly stroke is used for each round.
+       8: "rimo", // Reverse IM Order
        },
    activityType: {
        0: "generic",
diff --git a/src/stream.js b/src/stream.js
index f9b98a2..f329930 100644
--- a/src/stream.js
+++ b/src/stream.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/utils-hr-mesg.js b/src/utils-hr-mesg.js
index cbadbd1..7518ba5 100644
--- a/src/utils-hr-mesg.js
+++ b/src/utils-hr-mesg.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/utils-internal.js b/src/utils-internal.js
index dc29728..9de6ab4 100644
--- a/src/utils-internal.js
+++ b/src/utils-internal.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/src/utils-memo-glob.js b/src/utils-memo-glob.js
index 90dc209..207e26c 100644
--- a/src/utils-memo-glob.js
+++ b/src/utils-memo-glob.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 import Profile from "./profile.js";
diff --git a/src/utils.js b/src/utils.js
index 12674ff..4ffd2d6 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -5,8 +5,8 @@
 // Transfer (FIT) Protocol License.
 /////////////////////////////////////////////////////////////////////////////////////////////
 // ****WARNING****  This file is auto-generated!  Do NOT edit this file.
-// Profile Version = 21.170.0Release
-// Tag = production/release/21.170.0-0-g5991e72
+// Profile Version = 21.171.0Release
+// Tag = production/release/21.171.0-0-g57fed75
 /////////////////////////////////////////////////////////////////////////////////////////////
 
 
diff --git a/test/encode-activity-recipe.test.js b/test/encode-activity-recipe.test.js
index b214e59..6929386 100644
--- a/test/encode-activity-recipe.test.js
+++ b/test/encode-activity-recipe.test.js
@@ -168,7 +168,7 @@ test("Can encode a FIT Activity file", () => {
         timestamp: timestamp,
         numSessions: 1,
         localTimestamp: timestamp + localTimestampOffset,
-        totalTimerTime: timestamp = startTime,
+        totalTimerTime: timestamp - startTime,
     });
 
     try {