diff --git a/README.md b/README.md
index 3410a307..5e691924 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ Add this Action as a [step][job-step] to your project's GitHub Action Workflow f
 ```yaml
 - name: Send GitHub Action trigger data to Slack workflow
   id: slack
-  uses: slackapi/slack-github-action@v1.20.0
+  uses: slackapi/slack-github-action@v1.21.0
   env:
     SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
 ```
@@ -41,7 +41,7 @@ or
 ```yaml
 - name: Send custom JSON data to Slack workflow
   id: slack
-  uses: slackapi/slack-github-action@v1.20.0
+  uses: slackapi/slack-github-action@v1.21.0
   with:
     # This data can be any valid JSON from a previous step in the GitHub Action
     payload: |
@@ -59,7 +59,7 @@ or
 ```yaml
 - name: Send custom JSON data to Slack workflow
   id: slack
-  uses: slackapi/slack-github-action@v1.20.0
+  uses: slackapi/slack-github-action@v1.21.0
   with:
     payload-file-path: "./payload-slack-content.json"
   env:
@@ -85,7 +85,7 @@ Add this Action as a [step][job-step] to your project's GitHub Action Workflow f
 ```yaml
 - name: Post to a Slack channel
   id: slack
-  uses: slackapi/slack-github-action@v1.20.0
+  uses: slackapi/slack-github-action@v1.21.0
   with:
     # Slack channel id, channel name, or user id to post message.
     # See also: https://api.slack.com/methods/chat.postMessage#channels
@@ -101,7 +101,7 @@ Using JSON payload for constructing a message is also available:
 ```yaml
 - name: Post to a Slack channel
   id: slack
-  uses: slackapi/slack-github-action@v1.20.0
+  uses: slackapi/slack-github-action@v1.21.0
   with:
     # Slack channel id, channel name, or user id to post message.
     # See also: https://api.slack.com/methods/chat.postMessage#channels
@@ -130,7 +130,7 @@ If you would like to notify the real-time updates on a build status, you can mod
 
 ```yaml
 - id: slack
-  uses: slackapi/slack-github-action@v1.20.0
+  uses: slackapi/slack-github-action@v1.21.0
   with:
     channel-id: "CHANNEL_ID"
     payload: |
@@ -152,7 +152,7 @@ If you would like to notify the real-time updates on a build status, you can mod
       }
   env:
     SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN}}
-- uses: slackapi/slack-github-action@v1.20.0
+- uses: slackapi/slack-github-action@v1.21.0
   with:
     channel-id: "CHANNEL_ID"
     update-ts: ${{ steps.slack.outputs.ts }}
diff --git a/action.yml b/action.yml
index 4ea5cd91..518235f8 100644
--- a/action.yml
+++ b/action.yml
@@ -13,10 +13,15 @@ inputs:
   payload-file-path: # path to JSON payload to send to Slack via webhook
     description: 'path to JSON payload to send to Slack if webhook route. If not supplied, json from GitHub event will be sent instead. If payload is provided, it will take preference over this field'
     required: false
+  update-ts: # The timestamp of a previous message posted to update it instead of posting a new message
+    description: 'The timestamp of a previous message posted. It will update the existing message instead of posting a new message'
+    required: false
 outputs:
   time: # id of output
     description: 'The time'
-  thread_ts: # timestamp on the message that was posted when using bot token
+  thread_ts: # threaded timestamp on the message that was posted when using bot token
+    description: 'The timestamp on the message that was posted into Slack when using bot token'
+  ts: # timestamp of message posted
     description: 'The timestamp on the message that was posted into Slack when using bot token'
 runs:
   using: 'node12'
diff --git a/example-workflows/Technique_1_Slack_Workflow_Builder/JSON_payload.yml b/example-workflows/Technique_1_Slack_Workflow_Builder/JSON_payload.yml
index c83b579f..387a8120 100644
--- a/example-workflows/Technique_1_Slack_Workflow_Builder/JSON_payload.yml
+++ b/example-workflows/Technique_1_Slack_Workflow_Builder/JSON_payload.yml
@@ -7,7 +7,7 @@ jobs:
     steps:
     - name: Send GitHub trigger payload to Slack Workflow Builder
       id: slack
-      uses: slackapi/slack-github-action@v1.20.0
+      uses: slackapi/slack-github-action@v1.21.0
       with:
         payload: |
           {
diff --git a/example-workflows/Technique_1_Slack_Workflow_Builder/JSON_payload_from_file.yml b/example-workflows/Technique_1_Slack_Workflow_Builder/JSON_payload_from_file.yml
index 23397fe0..5e009027 100644
--- a/example-workflows/Technique_1_Slack_Workflow_Builder/JSON_payload_from_file.yml
+++ b/example-workflows/Technique_1_Slack_Workflow_Builder/JSON_payload_from_file.yml
@@ -7,7 +7,7 @@ jobs:
     steps:
     - name: Send GitHub trigger payload to Slack Workflow Builder
       id: slack
-      uses: slackapi/slack-github-action@v1.20.0
+      uses: slackapi/slack-github-action@v1.21.0
       with:
         payload-file-path: "./example-workflows/Technique_1_Slack_Workflow_Builder/payloads/example.json"
       env:
diff --git a/example-workflows/Technique_1_Slack_Workflow_Builder/default_GitHub_Trigger_payload.yml b/example-workflows/Technique_1_Slack_Workflow_Builder/default_GitHub_Trigger_payload.yml
index 95f3ae4f..94522b02 100644
--- a/example-workflows/Technique_1_Slack_Workflow_Builder/default_GitHub_Trigger_payload.yml
+++ b/example-workflows/Technique_1_Slack_Workflow_Builder/default_GitHub_Trigger_payload.yml
@@ -7,6 +7,6 @@ jobs:
     steps:
     - name: Send GitHub trigger payload to Slack Workflow Builder
       id: slack
-      uses: slackapi/slack-github-action@v1.20.0
+      uses: slackapi/slack-github-action@v1.21.0
       env:
         SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
diff --git a/example-workflows/Technique_2_Slack_App/JSON_payload.yml b/example-workflows/Technique_2_Slack_App/JSON_payload.yml
index 332d1dc5..ed16c46d 100644
--- a/example-workflows/Technique_2_Slack_App/JSON_payload.yml
+++ b/example-workflows/Technique_2_Slack_App/JSON_payload.yml
@@ -7,7 +7,7 @@ jobs:
     steps:
     - name: Send GitHub trigger payload to Slack Workflow Builder
       id: slack
-      uses: slackapi/slack-github-action@v1.20.0
+      uses: slackapi/slack-github-action@v1.21.0
       with:
         channel-id: 'SLACK_CHANNEL_ID' # ID of Slack Channel you want to post to
         payload: |
diff --git a/example-workflows/Technique_2_Slack_App/JSON_payload_as_text.yml b/example-workflows/Technique_2_Slack_App/JSON_payload_as_text.yml
index 857f0ff4..5ae04606 100644
--- a/example-workflows/Technique_2_Slack_App/JSON_payload_as_text.yml
+++ b/example-workflows/Technique_2_Slack_App/JSON_payload_as_text.yml
@@ -7,7 +7,7 @@ jobs:
     steps:
     - name: Send GitHub trigger payload to Slack Workflow Builder
       id: slack
-      uses: slackapi/slack-github-action@v1.20.0
+      uses: slackapi/slack-github-action@v1.21.0
       with:
         channel-id: 'SLACK_CHANNEL_ID' # ID of Slack Channel you want to post to
         payload: "{\"text\": \"posting from a github action\"}"
diff --git a/example-workflows/Technique_2_Slack_App/main.yml b/example-workflows/Technique_2_Slack_App/main.yml
index d81094b4..ca20b9b1 100644
--- a/example-workflows/Technique_2_Slack_App/main.yml
+++ b/example-workflows/Technique_2_Slack_App/main.yml
@@ -7,7 +7,7 @@ jobs:
     steps:
     - name: Publish to slack channel via bot token
       id: slack
-      uses: slackapi/slack-github-action@v1.20.0
+      uses: slackapi/slack-github-action@v1.21.0
       with:
         channel-id: 'SLACK_CHANNEL_ID' # ID of Slack Channel you want to post to
         slack-message: 'posting from a github action!' # The message you want to post
diff --git a/example-workflows/Technique_3_Slack_Incoming_Webhook/main.yml b/example-workflows/Technique_3_Slack_Incoming_Webhook/main.yml
index a6ad3de7..ba33b402 100644
--- a/example-workflows/Technique_3_Slack_Incoming_Webhook/main.yml
+++ b/example-workflows/Technique_3_Slack_Incoming_Webhook/main.yml
@@ -7,7 +7,7 @@ jobs:
     steps:
     - name: Send GitHub trigger payload to Slack Workflow Builder
       id: slack
-      uses: slackapi/slack-github-action@v1.20.0
+      uses: slackapi/slack-github-action@v1.21.0
       with:
         payload: |
           {
diff --git a/package-lock.json b/package-lock.json
index 2a16279b..56b86992 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "slack-github-action",
-  "version": "1.20.0",
+  "version": "1.21.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "slack-github-action",
-      "version": "1.20.0",
+      "version": "1.21.0",
       "license": "MIT",
       "dependencies": {
         "@actions/core": "^1.9.0",
diff --git a/package.json b/package.json
index 9fa22817..3dcbab70 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "slack-github-action",
-  "version": "1.20.0",
+  "version": "1.21.0",
   "description": "The official slack github action. Use this to send data into your Slack workspace",
   "main": "dist/index.js",
   "scripts": {