diff --git a/.github/workflows/automerge.yml b/.github/workflows/automerge.yml
new file mode 100644
index 0000000..2cbf113
--- /dev/null
+++ b/.github/workflows/automerge.yml
@@ -0,0 +1,30 @@
+name: automerge
+on:
+  pull_request:
+    types:
+      - labeled
+      - unlabeled
+      - synchronize
+      - opened
+      - edited
+      - ready_for_review
+      - reopened
+      - unlocked
+  pull_request_review:
+    types:
+      - submitted
+  check_suite:
+    types:
+      - completed
+  status: {}
+jobs:
+  automerge:
+    runs-on: ubuntu-latest
+    steps:
+      - name: automerge
+        uses: "pascalgn/automerge-action@7ab42e888a333bf77ce865bc84fedc6a365a3548"
+        env:
+          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+          MERGE_RETRIES: 30
+          MERGE_RETRY_SLEEP: 10000
+          MERGE_METHOD: merge
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 96be3ec..892d913 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -15,7 +15,7 @@ jobs:
       - uses: actions/checkout@v1
 
       - name: shellcheck
-        uses: azohra/shell-linter@v0.2.0
+        uses: azohra/shell-linter@v0.4.0
 
       - name: hadolint
         uses: brpaz/hadolint-action@master
diff --git a/conf.env b/conf.env
index abbd72b..5be1b51 100644
--- a/conf.env
+++ b/conf.env
@@ -1,2 +1,2 @@
-POSTFIX_VERSION=3.4.9-r0
+POSTFIX_VERSION=3.4.12-r0
 DOCKER_IMAGE=dcarrillo/postfix