diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 179095eb68aaf28e08ec33b6bd450edea72c982b..7a0e250178aef8b109ff21c96c40f25393e97e15 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,6 +10,8 @@ variables:
 docker_build_and_release_tests:
   stage: docker_build
   image: quay.io/podman/stable
+  variables:
+    IMAGE_TAG: $CI_REGISTRY_IMAGE:$CI_COMMIT_REF_SLUG
   script:
     - echo -n "$CI_JOB_TOKEN" | podman login -u gitlab-ci-token --password-stdin $CI_REGISTRY
     - cd test && podman build --build-arg ci_token=$CI_JOB_TOKEN --pull -t $IMAGE_TAG .
diff --git a/roles/mailman/templates/mm_cfg.py.j2 b/roles/mailman/templates/mm_cfg.py.j2
index 3fdbb8b87d802f5bed22c664c25d73b726e4545e..b0cd8f899fbdccd3fc0cde126210d0fedee3e701 100644
--- a/roles/mailman/templates/mm_cfg.py.j2
+++ b/roles/mailman/templates/mm_cfg.py.j2
@@ -113,7 +113,7 @@ DEFAULT_REPLY_GOES_TO_LIST = 0
 DEFAULT_MAX_DAYS_TO_HOLD = 15
 
 # rimuove le firme Dkim e Dk dalle mail in entrata a mailman
-REMOVE_DKIM_HEADERS = 'YES'
+REMOVE_DKIM_HEADERS = Yes
 
 
 #-------------------------------------------------------------
@@ -141,11 +141,14 @@ ARCHIVE_HTML_SANITIZER = 0
 # 3 = Discard
 DEFAULT_GENERIC_NONMEMBER_ACTION = 2
 
-# added by ale+blicero to limit recipient per send and avoid spam limit measures
-SMTP_MAX_RCPTS = 50
+# Enable VERP probes for better bounce detection, one in 10 emails.
+VERP_PROBES = Yes
+VERP_CONFIRMATIONS = Yes
+VERP_DELIVERY_INTERVAL = 10
 
-# Note - if you're looking for something that is imported from mm_cfg, but you
-# didn't find it above, it's probably in /usr/lib/mailman/Mailman/Defaults.py.
+# Limit recipient per send, avoid spam limit measures and limit blast
+# radius from delivery failures.
+SMTP_MAX_RCPTS = 10
 
 DEFAULT_SUBSCRIBE_POLICY = 3
 DEFAULT_LIST_ADVERTISED = No
diff --git a/roles/testdata-mailman/tasks/load.yml b/roles/testdata-mailman/tasks/load.yml
index efc7957e76c68e9dac11863d5f09eece4692f8be..41e12b5425bd8d67be2bc57aa54722f00ab1713b 100644
--- a/roles/testdata-mailman/tasks/load.yml
+++ b/roles/testdata-mailman/tasks/load.yml
@@ -13,4 +13,4 @@
 
 - name: Subscribe test user to test list
   shell: "echo uno@investici.org | in-container mailman-mailman /var/lib/mailman/bin/add_members -w n -a n -r - {{ test_list_name }}"
-  when: "mailman_test_list.exists"
+  when: "mailman_test_list.exists | default(False)"