The MailChimp Integration Extension just received a major update. The entire extension was rebuilt from the ground up using the MailChimp 3.0 API. This makes things much more stable and useable, and will lead to a host of new features in the future. For now, most of the features stay essentially the same.
If you are upgrading the MailChimp extension from a previous version to version 2.0, here are some items to keep in mind.
The information here primarily applies to upgrading the extension. If you are doing a new install, you can just review the documentation here.
Loading the new extension
Using the WP uploader
If you use the WP plugin uploader, you will need to deactivate the extension and also delete it via the plugin admin panel.
Note that this will clear out your settings as well so will need to reconfigure the settings with your API key and list ID.
It is highly recommended that you deactivate the current extension before loading the new version.
If you are using FTP, deactivate the extension in the plugin panel, then delete the current version’s files via FTP before loading the new files. If you do not delete the previous version’s files, you will end up seeing two extensions in the plugin admin panel, one of which does not function (the old version).
Additionally, if you did not deactivate the previous version prior to loading the new files, it may appear that the extension is broken. This means that you have a file active from the previous version that should not be there. All of the old version’s files should be removed prior to activating the new version.
Once the new files are loaded, reactivate the extension.
The new version makes use of the MailChimp API version 3.0. There are a lot of great new features in the 3.0 API. However, there are some functions that no longer are supported by the API, and so certain settings have been removed from the extension.
The option to send a welcome message has been removed as a result of this. For some users this may not matter, especially if you did not have this setting enabled (which it was not by default). But if you did use this feature in the past, keep in mind that it has been removed. (Note: and opt-in message is still an option, and the process of adding a user without the double opt-in is actually a cleaner process in the new API.)
Similarly, there was an option in both the delete and deactivate menus to delete the user and send a notification (from MailChimp). This is also no longer an option for the same reason as the welcome message above. Deleting the user is still an option, just not delete & send notification.
One improvement to the admin panel that many people will find helpful is that you may now map your mail merge fields directly from the admin panel. You no longer need to do this with a filter function.
If you have mail merge fields to map and you are using a filter function, you have a couple of options with the update. First, you can probably just delete the filter function and map your fields in the admin panel. This is recommended as it will be easier to manage.
Alternatively, you can leave your filter function in place and choose to not set and mapping settings. The filter will continue to map custom fields the same as before.
What you cannot do is both. While this may not necessarily break anything, you’ll essentially be doubling each field in the array that gets passed to MailChimp. You should either remove the filter function or not set the fields in the admin panel. One or the other, but not both.
MailChimp API Playground
MailChimp provides a “Playground” for working with the API. If you need to do any testing, you may end up using this. The Playground is located at http://developer.mailchimp.com.
I have some information specific to troubleshooting using the Playground here.
Keep in mind that the “Playground” is different from a developer’s “Sandbox” in that it is actually live data. So anything you do there to your list is a real action. Generally, a “sandbox” is completely test data and is not live. Keep this difference in mind if you are testing on your actual live list.