Suggestions for WPMU Migration (advanced)

We have a multisite network with a few hundred sites. We are currently merging with another company and migrating our sites. However we have a few clients who have decided to jump ship and are asking for their website data.

I understand the basics of WP migration and have worked with single installations, but not network to single site or network to network. What I’m looking for are specific directions to provide client new provider.

I have these things in order for them:

• Content export
• Blog.dir files (media)
• Parent and child theme
• Database for site-id

They may not be familiar with this process, and I am only as familiar as what I’ve researched online. I cannot find an intuitive step by step approach to provide. I’m not concerned with their ability to work with the data as much as ensuring I am providing accurate information etc.

What steps and instructions should I provide along with data?

I’m looking for insight, suggestions, tips, and any external resources. Ideally this process would be 100% manual involving zero third-party WP plugins. Also, we do not intend to provide copies of all the plugins as many of them are licensed etc. Per our agreement they are responsible for working it out.

Yes, give them the four things you mentioned. The main thing would be the .xml file that is created when using the WordPress export feature. Keep in mind that you need to keep the media on your server too if you want them to be able to import it with the .xml file. The file just contains links to the media files.

You might want to provide instructions for different situations. Their new site might be in:

1. Multisite that uses sub-domains
2. Multisite that uses sub-folders
3. Multisite that allows mapped domains
4. Single site

You should test all of them with one test site and document the steps while you are doing it.

Here are instructions for moving from a multisite to a single site: http://www.wpbeginner.com/wp-tutorials/how-to-move-a-site-from-wordpress-multisite-to-single-install/