diff --git a/README.md b/README.md
index 980d4c3..c1d8102 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ By default, each time you save a `bindzone` file, the script will look for the D
 Patterns
 --------
 
-In order to be detected, the DNS serial number must match the following pattern:
+In order to be detected, the DNS serial number must match one the following pattern:
 
 * `YYYYMMDDXX ; serial`
   - `YYYY` is the year (4 digits);
@@ -38,8 +38,65 @@ In order to be detected, the DNS serial number must match the following pattern:
   - the word `serial` is not case-sensitive;
   - there can be any number of blanks on each sides of the semicolon.
 
+* `XX ; serial`
+  - `XX` is any non-negative number (1 or more digits);
+  - the word `serial` is not case-sensitive;
+  - there can be any number of blanks on each sides of the semicolon.
+
 
 Configuration
 -------------
 
-You can turn off the automatic serial update by setting `let g:dnsserial_auto_update = 0` in your vimrc.
+You can set several configuration variables in your vimrc:
+
+* `g:dnsserial_auto_update`: Defines whether or not the serial is updated when the zone file is saved (default is 1, set it to 0 to disable).
+* `g:dnsserial_custom_patterns`: List of customs patterns that will be added to the default ones. Order matters, the first matching patters will be used. Customs patterns will be tested before the default ones.
+* `g:dnsserial_patterns`: List of default patterns. It is not advised to change it.
+
+
+Custom patterns
+---------------
+
+A pattern is defined by a dictionary with two keys: `regex` and `matching`.
+
+**regex**
+
+Contains the regular expression that will be used to search the document for the serial number. All the components of the serial number must be captured with parenthesis.
+
+**matching**
+
+This is a list of every components of the serial number. Each component is defined by a dictionary. The `type` key must be present and contain one of the allowed types. Depending on the type, several additional keys might be defined. Authorized types and their options are:
+
+* `raw`: Raw string.
+* `integer`: An integer that will be incremented.
+- `offset` (int): set the offset by which the integer is incremented. Default is 1.
+- `padding` (int): Force the integer to be 0-padded on the associated number of digits.
+- `date_reset` (bool): If set to 1 and a the serial contains a `date`, the integer will be reseted to 0 if the date is updated. Default is 0.
+* `date`: A formated date that will be updated to the current one.
+- `fmt` (string, mandatory) : the date format according to the `strftime()` specifications. See `:help strftime` for more details.
+
+**examples**
+
+A simple pattern matching a serial defined as an integer and followed by a comment starting by the word `serial` is:
+
+```json
+{
+  'regex': '\(\d\+\)\s*;\s*\cserial',
+  'matching': [
+    {'type': 'integer'}
+  ]
+}
+```
+
+The same example, but having the serial number starting by the current date (YYYYMMDD) and the integer padded on two digits:
+
+
+```json
+{
+  'regex': '\(\d\{8}\)\(\d\+\)\s*;\s*\cserial',
+  'matching': [
+    {'type': 'date', 'fmt': '%Y%m%d'},
+    {'type': 'integer', 'padding': 2, 'date_reset': 1}
+  ]
+}
+```
diff --git a/autoload/dnsserial.vim b/autoload/dnsserial.vim
index c72b448..15cca4c 100644
--- a/autoload/dnsserial.vim
+++ b/autoload/dnsserial.vim
@@ -12,28 +12,59 @@
 " See the License for the specific language governing permissions and
 " limitations under the License.
 
-function! s:IncrementSerial(old_date, old_nb)
-    let curr_date = strftime("%Y%m%d")
-    if a:old_date ==? curr_date
-        let curr_nb = a:old_nb + 1
-        if curr_nb < 10
-            let curr_nb = "0".curr_nb
+
+function! s:HasDateChanged(pattern, old_matchlist)
+    let i = 0
+    for matching in a:pattern.matching
+        if matching.type ==? 'date'
+            let old_date = a:old_matchlist[i]
+            let new_date = strftime(matching.fmt)
+            if old_date !=? new_date
+                return 1
+            endif
         endif
-    else
-        let curr_nb = "01"
+        let i += 1
+    endfor
+    return 0
+endfunction
+
+function! s:GetNewValue(matching, old_value, date_changed)
+    if a:matching.type ==? 'date'
+        return strftime(a:matching.fmt)
+    elseif a:matching.type ==? 'integer'
+        let nb = a:old_value + get(a:matching, 'offset', 1)
+        if a:date_changed && get(a:matching, 'date_reset', 0)
+            let nb = 0
+        endif
+        return printf('%0' . get(a:matching, 'padding', 1) . 'd', nb)
     endif
-    return curr_date.curr_nb
+    return a:old_value
+endfunction
+
+function! s:GetNewSerial(pattern, old_matchlist)
+    let date_changed = s:HasDateChanged(a:pattern, a:old_matchlist)
+    let new_serial = []
+    let i = 0
+    for matching in a:pattern.matching
+        let new_value = s:GetNewValue(matching, a:old_matchlist[i], date_changed)
+        call add(new_serial, new_value)
+        let i += 1
+    endfor
+    return join(new_serial, '')
 endfunction
 
 function! dnsserial#DNSSerialUpdate()
-    let pattern = '\(\d\{8}\)\(\d\+\)\s*;\s*\cserial'
-    if search(pattern) == 0
-        echom "No serial found."
-        return 0
-    endif
-    let old_pattern = matchlist(getline('.'), pattern)
-    let old_serial = old_pattern[1].old_pattern[2]
-    let new_serial = s:IncrementSerial(old_pattern[1], old_pattern[2])
-    execute "s/".old_serial."/".new_serial."/"
-    echom "Serial updated to ".new_serial."."
+    let patterns = g:dnsserial_custom_patterns + g:dnsserial_patterns
+    for pattern in patterns
+        if search(pattern.regex) != 0
+            let offset = len(pattern.matching)
+            let old_matchlist = matchlist(getline('.'), pattern.regex)[1:offset]
+            let old_serial = join(old_matchlist, '')
+            let new_serial = s:GetNewSerial(pattern, old_matchlist)
+            execute "s/" . old_serial . "/" . new_serial . "/"
+            echom "Serial updated to " . new_serial . "."
+            return 0
+        endif
+    endfor
+    echom "No serial found."
 endfunction
diff --git a/plugin/dnsserial.vim b/plugin/dnsserial.vim
index 0607bde..7de4233 100644
--- a/plugin/dnsserial.vim
+++ b/plugin/dnsserial.vim
@@ -12,4 +12,28 @@
 " See the License for the specific language governing permissions and
 " limitations under the License.
 
+
+if !exists('g:dnsserial_custom_patterns')
+    let g:dnsserial_custom_patterns = []
+endif
+
+if !exists('g:dnsserial_patterns')
+    let g:dnsserial_patterns = [
+        \{
+            \'regex': '\(\d\{8}\)\(\d\+\)\s*;\s*\cserial',
+            \'matching': [
+                \{'type': 'date', 'fmt': '%Y%m%d'},
+                \{'type': 'integer', 'padding': 2, 'date_reset': 1}
+            \]
+        \},
+        \{
+            \'regex': '\(\d\+\)\s*;\s*\cserial',
+            \'matching': [
+                \{'type': 'integer'}
+            \]
+        \},
+    \]
+endif
+
+
 command! DNSSerialUpdate call dnsserial#DNSSerialUpdate()