diff --git a/order_point.py b/order_point.py
index cc92bd01a5..7d562101fd 100644
--- a/order_point.py
+++ b/order_point.py
@@ -125,10 +125,8 @@ class OrderPoint(ModelSQL, ModelView):
     def __register__(cls, module_name):
         cursor = Transaction().connection.cursor()
         sql_table = cls.__table__()
-
-        # Migration from 2.2
         table = cls.__table_handler__(module_name)
-        table.drop_constraint('check_min_max_quantity')
+
         # Migration from 4.2
         table.drop_constraint('check_max_qty_greater_min_qty')
         table.not_null_action('min_quantity', 'remove')
diff --git a/purchase_request.py b/purchase_request.py
index b72f7603bb..97db6c100d 100644
--- a/purchase_request.py
+++ b/purchase_request.py
@@ -29,18 +29,6 @@ class PurchaseRequest(metaclass=PoolMeta):
     'Purchase Request'
     __name__ = 'purchase.request'
 
-    @classmethod
-    def __register__(cls, module_name):
-        cursor = Transaction().connection.cursor()
-        sql_table = cls.__table__()
-        super(PurchaseRequest, cls).__register__(module_name)
-
-        # Migration from 2.0: empty order point origin is -1 instead of 0
-        cursor.execute(*sql_table.update(
-                columns=[sql_table.origin],
-                values=['stock.order_point,-1'],
-                where=sql_table.origin == 'stock.order_point,0'))
-
     @classmethod
     def _get_origin(cls):
         origins = super(PurchaseRequest, cls)._get_origin()
diff --git a/shipment.py b/shipment.py
index 9ed01965d0..6ef998f4ba 100644
--- a/shipment.py
+++ b/shipment.py
@@ -2,9 +2,6 @@
 # this repository contains the full copyright notices and license terms.
 import datetime
 
-from sql import Table
-from sql.functions import Overlay, Position
-
 from trytond.model import ModelView, ModelSQL
 from trytond.transaction import Transaction
 from trytond.pool import Pool
@@ -15,28 +12,6 @@ __all__ = ['ShipmentInternal']
 class ShipmentInternal(ModelSQL, ModelView):
     __name__ = 'stock.shipment.internal'
 
-    @classmethod
-    def __register__(cls, module_name):
-        cursor = Transaction().connection.cursor()
-        model_data = Table('ir_model_data')
-        model = Table('ir_model')
-        # Migration from 1.2: packing renamed into shipment
-        cursor.execute(*model_data.update(
-                columns=[model_data.fs_id],
-                values=[Overlay(model_data.fs_id, 'shipment',
-                        Position('packing', model_data.fs_id),
-                        len('packing'))],
-                where=model_data.fs_id.like('%packing%')
-                & (model_data.module == module_name)))
-        cursor.execute(*model.update(
-                columns=[model.model],
-                values=[Overlay(model.model, 'shipment',
-                        Position('packing', model.model),
-                        len('packing'))],
-                where=model.model.like('%packing%')
-                & (model.module == module_name)))
-        super(ShipmentInternal, cls).__register__(module_name)
-
     @classmethod
     def generate_internal_shipment(cls, clean=True):
         """