New Install / Upgrade Questions --1.2.6. to 1.3.8a

I am trying to upgrade a now non-working 1.2.6 site to 1.3.8a for someone. They ran into problems because the host upgraded SQL last week.

There is only 1 item sold in the store, and he uses Authorize.net

With the complexities involved in the upgrade from 1.2.6 - 1.3.8a, I have been thinking about just a new installation.

Questions:

1. Can I utiilize the old database with a new install?

2. Will it be difficult to set up Authorize.net again?

3. For an upgrade (if I do it), where do I install to? In the 1.2.6 directory, over the existing files?? Then run zc_install?

The files and database are backed up already.

Thanks

The files and database are backed up already.
With this done and copied to safe locations in triplicate...

And if the sql change has the shop not functioning then you can just overload the files and run zc_install.... you will be presented with the upgrade database option and know that sometimes one has to run the upgrade for a single version at a time.

Bigger issue will be the template files...as with 1.3.x the tables used earlier are not supported fully and the template will most likely have to be rebuilt

You can do your upgrade using your current files / databases as they will be overwritten / updated when you upload the new files.

Two things:

• Templates previous to v1.3 will not work and will have to be recoded
• upgrading your database will require about 11 upgrades, they will be listed by version number and you need to do them one at a time; it will make more sense once you see it action