I too am interested on how to upgrade from 1.6 to 1.2.1. I did it via magento connect on my dev install , all seemed to work well i had no error message , but now i can’t access the admin anymore and in the front end, i can no longer use the cart.
Every time i tried to add an item to my cart, it ended up on the page where it says my cart is empty. I can’t log in to the front end either.
Has anyone had those issues when upgrading from 1.6 to 1.2.1 ?
I would also like to know if anyone has any experience with this?
As Magento Connect (Downloader) is EXTREMELY unreliable and hangs every time, I have decided to do a clean install instead. However, I have changed a number of template files, so I have to go through them one by one with WinMerge.
Are there any known issues with upgrading from 1.6 to 1.2.1?
It’s for your own sake, DO NOT try to upgrade using Madento Connect. It never worked for me. The easiest way to upgrade is to download the new full version, unpack it then upload it to the server and restart install process using the existing database. You need to back up your database and all files in media directory as well as other customized files in other directories before you upgrade. Try to keep these custom files intact in their original places and upload all others from the new full version. The re-install process should be straightforward as long as you’ve saved and input all your previous environment such as database name, password, base url, secure url, admin login, Magento encryption key and so on.