Get ready for some eShop issues prior to the big firmware launch. The main issue being...the lack of the eShop at all.
On account of the upcoming system update, which will be available by 8 December, Nintendo eShop will be unavailable for a limited period while the main server undergoes essential maintenance.
Once work on the server has been completed and you have performed the update on your Nintendo 3DS system, you will be able to visit Nintendo eShop as usual and take advantage of the new features. A SpotPass notification summarising all the improvements to Nintendo eShop will be sent out soon.
Nintendo eShop team