diff --git a/ext/custom-addons/dp_custom/models/res_partner.py b/ext/custom-addons/dp_custom/models/res_partner.py
index d0544165..b99ecebc 100644
--- a/ext/custom-addons/dp_custom/models/res_partner.py
+++ b/ext/custom-addons/dp_custom/models/res_partner.py
@@ -56,6 +56,7 @@ class Partner(models.Model):
     active = fields.Boolean(track_visibility='onchange')
     portal_export_pending = fields.Boolean(string='Portal Export ausständig')
     date_vat_check = fields.Date(string='Datum der letzten UID-Prüfung')
+    collective_bill = fields.Boolean(string='Sammelrechnung')
 
     _sql_constraints = [
         ('ref_uniq', 'unique(ref)', 'Die Interne Referenz muss eindeutig sein'),
diff --git a/ext/custom-addons/dp_custom/models/sale.py b/ext/custom-addons/dp_custom/models/sale.py
index a0734926..1f7ad61f 100644
--- a/ext/custom-addons/dp_custom/models/sale.py
+++ b/ext/custom-addons/dp_custom/models/sale.py
@@ -21,7 +21,8 @@
 from datetime import datetime
 
 from odoo import api, fields, models, _
-from odoo.exceptions import ValidationError
+from odoo.tools import float_is_zero
+from odoo.exceptions import ValidationError, UserError
 from odoo.tools import DEFAULT_SERVER_DATETIME_FORMAT
 
 
@@ -31,13 +32,13 @@ class SaleOrder(models.Model):
 
     ASSEMBLY_STATES = [('approved', 'Produktionsfreigabe'),
                        ('started', 'Produktion begonnen'),
-                       ('done', 'Produktions fertig'),
+                       ('done', 'Produktion fertig'),
                        ('packed', 'Verpackt'),
                        ('delivered', 'Geliefert')]
 
     assembled = fields.Boolean(string='Zusammengebaut')
     line_id = fields.Many2one(comodel_name='res.line', string='Produktionslinie')
-    assembly_state = fields.Selection(ASSEMBLY_STATES, string="Status PG")
+    assembly_state = fields.Selection(ASSEMBLY_STATES, string="Status PG", track_visibility='onchange')
     quote_name = fields.Char(compute='_compute_quote_name')
     internal_notes = fields.Text()
     assembly_notes = fields.Text()
@@ -199,6 +200,70 @@ class SaleOrder(models.Model):
         return ['origin', 'client_order_ref', 'note', 'date_order', 'assembled', 'line_id', 'partner_id',
                 'fiscal_position_id', 'user_id', 'payment_term_id', 'partner_delivery_id', 'partner_invoice_id']
 
+    @api.multi
+    def write(self, vals):
+        res = super(SaleOrder, self).write(vals)
+        if vals.get('assembly_state', False) and vals.get('assembly_state', False) == 'done':
+            self.message_post(body='Produktion fertig')
+
+        return res
+
+    @api.multi
+    def action_invoice_create(self, grouped=False, final=False):
+        inv_obj = self.env['account.invoice']
+        precision = self.env['decimal.precision'].precision_get('Product Unit of Measure')
+        invoices = {}
+        references = {}
+        for order in self:
+            collective_bill = order.partner_id.collective_bill and "x" or order.id
+            group_key = order.id if grouped else (collective_bill, order.partner_invoice_id.id, order.currency_id.id)
+            for line in order.order_line.sorted(key=lambda l: l.qty_to_invoice < 0):
+                if float_is_zero(line.qty_to_invoice, precision_digits=precision):
+                    continue
+                if group_key not in invoices:
+                    inv_data = order._prepare_invoice()
+                    invoice = inv_obj.create(inv_data)
+                    references[invoice] = order
+                    invoices[group_key] = invoice
+                elif group_key in invoices:
+                    vals = {}
+                    if order.name not in invoices[group_key].origin.split(', '):
+                        vals['origin'] = invoices[group_key].origin + ', ' + order.name
+                    if order.client_order_ref and order.client_order_ref not in invoices[group_key].name.split(
+                            ', ') and order.client_order_ref != invoices[group_key].name:
+                        vals['name'] = invoices[group_key].name + ', ' + order.client_order_ref
+                    invoices[group_key].write(vals)
+                if line.qty_to_invoice > 0:
+                    line.invoice_line_create(invoices[group_key].id, line.qty_to_invoice)
+                elif line.qty_to_invoice < 0 and final:
+                    line.invoice_line_create(invoices[group_key].id, line.qty_to_invoice)
+
+            if references.get(invoices.get(group_key)):
+                if order not in references[invoices[group_key]]:
+                    references[invoice] = references[invoice] | order
+
+        if not invoices:
+            raise UserError(_('There is no invoicable line.'))
+
+        for invoice in invoices.values():
+            if not invoice.invoice_line_ids:
+                raise UserError(_('There is no invoicable line.'))
+            # If invoice is negative, do a refund invoice instead
+            if invoice.amount_untaxed < 0:
+                invoice.type = 'out_refund'
+                for line in invoice.invoice_line_ids:
+                    line.quantity = -line.quantity
+            # Use additional field helper function (for account extensions)
+            for line in invoice.invoice_line_ids:
+                line._set_additional_fields(invoice)
+            # Necessary to force computation of taxes. In account_invoice, they are triggered
+            # by onchanges, which are not triggered when doing a create.
+            invoice.compute_taxes()
+            invoice.message_post_with_view('mail.message_origin_link',
+                                           values={'self': invoice, 'origin': references[invoice]},
+                                           subtype_id=self.env.ref('mail.mt_note').id)
+        return [inv.id for inv in invoices.values()]
+
 
 class SaleOrderLine(models.Model):
     _inherit = 'sale.order.line'
diff --git a/ext/custom-addons/dp_custom/views/res_partner_views.xml b/ext/custom-addons/dp_custom/views/res_partner_views.xml
index c16384f3..617e6ca9 100644
--- a/ext/custom-addons/dp_custom/views/res_partner_views.xml
+++ b/ext/custom-addons/dp_custom/views/res_partner_views.xml
@@ -54,6 +54,10 @@
                 <field name="endkunde"/>
                 <field name="partner_sector_id"/>
             </xpath>
+
+            <xpath expr="//field[@name='property_payment_term_id']" position="before">
+                <field name="collective_bill"/>
+            </xpath>
         </field>
     </record>