I have a fresh WordPress installed for a new site. I love MailChimp and Contact Form 7 for other websites I have worked on. It would appear that this plugin should marry them quite nicely. I installed the Contact Form 7 plugin, then the Contact-Form-7: 3rd-Party Integration plugin. I did not have the Contact Form 7 Modules plugin previously installed, but it appears in my plugins as Contact Form 7 Modules: Hidden Fields after the 3-rd plugin installation.
The version of this plugin says 1.2 and that there is a 1.2.1 update (which I checked and that is true), but the automatic update is not being applied. I tried installing it separately and it seemed to work fine, but then I had two instances of the same plugin (1.2 and 1.2.1) where the 1.2 version was saying it could still be updated (very odd). Obviously, you're not here to support the Contact Form 7 Modules: Hidden Fields plugin, but I wanted to share my experience and see if you had any ideas. Also, I'm curious if I even have to update to version 1.2.1.