THIS ADD-ON IS NOT COMPATIBLE WITH CONCRETE VERSION 8 BECAUSE THEY HAVE MADE CHANGES TO THE CORE. I'M WORKING ON A NEW VERSION BUT THIS IS TAKING TIME. IN ADDITION, MAILCHIMP HAS MADE CHANGES TO MANDRILL AND IT IS NO LONGER FREE SO I HAVE NO MEANS OF DOING TESTS WITHOUT GETTING A PAID ACCOUNT WHICH WOULD COST ME MORE MONEY THAN THIS ADD-ON GENERATES.
The Mail Service Integration package integrates mail services into Concrete, replacing the default mail service by one of the services provided by this package. At this moment it supports Mailgun, Mandrill (Mailchimp) and Sendgrid and I'll be adding more mail services such as Mailjet in the near future. Configure and enable a service of your choice and Concrete uses this service to send all emails.
3RD PARTY API KEYS REQUIRED TO USE THIS ADD-ON
This package uses 3rd party api's (Mailgun, Sendgrid and Mandrill) for which you need to register with the corresponding providers and create api-keys. These parties offer free accounts as well as paid accounts.
Support on creating and configuring these accounts is not included in the support for this add-on, as these are services are offered by 3rd parties. Configuration is quite straightforward however though, and if you can't figure it out I will be glad to help you out.
PHP VERSION 5.4 OR GREATER REQUIRED TO USE THIS ADD-ON
Though Concrete 5.7 runs on PHP version 5.3, this add-on requires PHP version 5.4 to run. That is becauses those requirements are derived from the 3rd part libraries used in this add-on. Check the PHP version used on your hosting environment to see if you meet this requirement. This add-on will not install if your PHP version is less than 5.4.
How does it work?
At installation the package modifies your configuration file and installs a ServiceProvider that overrides the default service provider for the email service. So every time Concrete calls the email service, our service provider returns the email service you configured and enabled, making Concrete use that service. The configuration file is the file used to override or add configuration settings for your website. It is empty by default.
All emails sent by Concrete, such as password reset links and other notifications, will then be sent using the configured email service.
You can enable one service at a time. If you disable all services, Concrete will use the default mail service.
When to use this package?
The benefit of using contract mailers like Mailgun is that you can send large batches of email without overloading your SMTP server (Concrete uses SMTP by default). Another benefit is that you can use the extra services provided by the contract mailers to track your emails.