Revert to old version of WP

I absolutely must revert to an older version of Wordpress. I am wondering, what the easiest way to do this is, without affecting the existing content. The version of Wordpress that I need is already installed on another domain. Would it be as simple as downloading the root files and transferring them to the new domain's root? What php files do I need to change? What code? Is this easiest route to go?
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Dave BaldwinFixer of ProblemsCommented:
You need to get copies of the databases for the two versions and compare them to see what changes have been made.
mikegeorge2Author Commented:
Long story-- but the database on the new install is empty.

Of course, the new WP installation is the connected to a DB, but it's empty.

So I am wondering: Can I take my old WP installation from old domain and just DL it to my hard drive. Then, I was thinking I would just delete everything on the new install, except wp-config.

Then, upload my entire old WP from my old domain, to my new domain with a new WP-config file.

Could it be that simple?
Dave BaldwinFixer of ProblemsCommented:
I don't think so.  In addition to the files, you do need the old database but you have to change the URLs that are in it to match the new domain or it won't work.  The database is where all the info is in Wordpress.

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Jason C. LevineDon't talk to me.Commented:
Dave is probably right in that it won't work but it also depends on how far back you need to go.  More recent versions of WordPress have changed the database structure in subtle ways and that alone may sink your download/upload attempt.  

In theory, you could transfer the theme easily enough and move the data containing just the content around with some very clever queries or one of the better import/export plugins.

I've done something like this before using MS Access with MyODBC as a bridge between the two MySQL databases.  It took awhile and mapping columns wasn't the most fun I've ever had, but it worked.
FYI From the Wordpress forums

Unless you have a backup that you can restore from, downgrading is an immensely difficult (if not impossible) process, which is why backing up before upgrading is strongly recommended both in the upgrade instructions and automatic upgrade interface.
Jason C. LevineDon't talk to me.Commented:
This question has been classified as abandoned and is closed as part of the Cleanup Program. See the recommendation for more details.
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