If I upgrade from 2.5 to 2.7, do I use the new wp-config from 2.7 or the 2.5 one

You can just use the same file, but somewhere along the line the config file can change, for example when the secret keys were added. In that case you may want to make a new config file from the WP pack that you downloaded. The secret keys were added with 2.6, so my advice would be to make yourself a new config file for this upgrade.

How would I make a new config file? Not sure what you mean.

Did you just mean that I should copy over the settings from the old one to the new one?

You should copy over the database name, db username, password, and db connection. Make sure the db encoding matches…probably utf8 and make sure the table prefix matches…probably wp_

Then go to the url provided in the 2.7 config file and get the keys…just copy them from the webpage and past them in-place of what is there. Save and all should be well.

See the first part of the second video in the following post for more info…note I am using Cpanel file manager, but you would do the same thing even if you are using an FTP client.

https://educhalk.org/blog/?p=17

Alright. Great. Thanks very much. One morething. Can I change the keys I get from api.www.ads-software.com/secret-key/1.1/ at a later time? Or am I supposed to stay with these from this point on?

I suppose you could change them…haven’t really though about it, but see no reason who not…I don’t think anything is stored in the db from them.

Okay I might be mistaken or most likely am but I think that I saw something like the key in a database. Could have been something else. Will keep this in mind

Ya, cant find it now, but I think I saw it. At any rate, thank you for all of your assistance with this issue