diff --git a/postfix/tasks/main.yml b/postfix/tasks/main.yml
index 6272be33..a1b5a424 100644
--- a/postfix/tasks/main.yml
+++ b/postfix/tasks/main.yml
@@ -1,6 +1,6 @@
 ---
 - name: check if main.cf is default
-  shell: 'grep -v -E "^(myhostname|mydestination|mailbox_command)" /etc/postfix/main.cf  | md5sum -'
+  shell: 'grep -v -E "^(myhostname|mydestination|mailbox_command)" /etc/postfix/main.cf | md5sum -'
   changed_when: False
   check_mode: no
   register: default_main_cf
diff --git a/postfix/tasks/minimal.yml b/postfix/tasks/minimal.yml
index 99b99003..d1e4b4c5 100644
--- a/postfix/tasks/minimal.yml
+++ b/postfix/tasks/minimal.yml
@@ -18,7 +18,7 @@
     force: yes
   notify: restart postfix
   when: postfix_force_main_cf == True or
-        default_main_cf.stdout == "5450c05d65878e99dad696c7c722e511  -" or
-        default_main_cf.stdout == "30022953f1f61f002bfb72e163ecb27e  -"
+        postfix_maincf_md5_jessie in default_main_cf.stdout or
+        postfix_maincf_md5_stretch in default_main_cf.stdout
   tags:
   - postfix
diff --git a/postfix/tasks/packmail.yml b/postfix/tasks/packmail.yml
index 3ffd096f..de9ee7ad 100644
--- a/postfix/tasks/packmail.yml
+++ b/postfix/tasks/packmail.yml
@@ -21,8 +21,8 @@
     force: yes
   notify: restart postfix
   when: postfix_force_main_cf == True or
-        default_main_cf.stdout == "5450c05d65878e99dad696c7c722e511  -" or
-        default_main_cf.stdout == "30022953f1f61f002bfb72e163ecb27e  -"
+        postfix_maincf_md5_jessie in default_main_cf.stdout or
+        postfix_maincf_md5_stretch in default_main_cf.stdout
   tags:
   - postfix
 
diff --git a/postfix/vars/main.yml b/postfix/vars/main.yml
new file mode 100644
index 00000000..e8a773c9
--- /dev/null
+++ b/postfix/vars/main.yml
@@ -0,0 +1,5 @@
+---
+## MD5 hash of default main.cf filter, obtained with this command :
+# grep -v -E "^(myhostname|mydestination|mailbox_command)" /etc/postfix/main.cf  | md5sum -
+postfix_maincf_md5_jessie: "5450c05d65878e99dad696c7c722e511"
+postfix_maincf_md5_stretch: "30022953f1f61f002bfb72e163ecb27e"