diff --git a/issue4727.diff b/issue4727.diff
new file mode 100644
index 0000000..2d0e1a2
--- /dev/null
+++ b/issue4727.diff
@@ -0,0 +1,51 @@
+diff -r 5b250b63a721 invoice.py
+--- a/trytond/trytond/modules/account_invoice/invoice.py	Thu Jan 07 12:11:44 2016 +0100
++++ b/trytond/trytond/modules/account_invoice/invoice.py	Thu Jan 07 12:55:36 2016 +0100
+@@ -1649,6 +1649,8 @@
+                     'uses the same account (%(account)s).'),
+                 })
+ 
++        cls._check_modify_exclude = {'note', 'origin'}
++
+     @classmethod
+     def __register__(cls, module_name):
+         pool = Pool()
+@@ -1957,17 +1959,18 @@
+         return [(None, '')] + [(m.model, m.name) for m in models]
+ 
+     @classmethod
+-    def check_modify(cls, lines):
++    def check_modify(cls, lines, fields=None):
+         '''
+         Check if the lines can be modified
+         '''
+-        for line in lines:
+-            if (line.invoice
+-                    and line.invoice.state in ('posted', 'paid')):
+-                cls.raise_user_error('modify', {
+-                        'line': line.rec_name,
+-                        'invoice': line.invoice.rec_name
+-                        })
++        if fields is None or fields - cls._check_modify_exclude:
++            for line in lines:
++                if (line.invoice
++                        and line.invoice.state in ('posted', 'paid')):
++                    cls.raise_user_error('modify', {
++                            'line': line.rec_name,
++                            'invoice': line.invoice.rec_name
++                            })
+ 
+     @classmethod
+     def delete(cls, lines):
+@@ -1976,8 +1979,9 @@
+ 
+     @classmethod
+     def write(cls, *args):
+-        lines = sum(args[0::2], [])
+-        cls.check_modify(lines)
++        actions = iter(args)
++        for lines, values in zip(actions, actions):
++            cls.check_modify(lines, set(values))
+         super(InvoiceLine, cls).write(*args)
+ 
+     @classmethod
diff --git a/series b/series
index 18fd9f0..3f454fe 100644
--- a/series
+++ b/series
@@ -76,6 +76,7 @@ account_chart_speedup.diff
 # Ignore next patches
 #incremental_wait_in_retries.diff
 # Uncomment in calfruitos
+#issue4727.diff
 #fix_rounding_in_sync_inventory_to_outgoing.patch
 #chart_not_translatable.diff
 #024726_account_bank_remove_company.diff