Received this today from sainsbury's, so thought I would make other's who might not have had this message aware.
We're making some important changes to Sainsbury's Online Groceries to bring you an even better website.
However, this means our online groceries site will be unavailable from 2pm Friday 14 September until 11am Sunday 16 September while we update it.
This only affects Sainsbury's Online Groceries - you'll still be able to use all other Sainsbury's sites just like normal.
How will this affect you?
During this time you won't be able to shop for groceries online or change an order you've already placed. But if you've booked a delivery slot for this period, don't worry - you'll still have your shopping delivered as normal.
Write down your username today... You'll need to enter it when you first login to the new site.
Sorry for any inconvenience - we'll be back before you know it with a site that's better than ever. We'll tell you about all the great new features soon!