Currently, some services use Mandrill to send transactionnel mails.

They're killing free accounts 27 April, so we need to migrate to another provider or our own infrastructure.

Mail received:

Going forward, all Mandrill users will be required to have a paid monthly MailChimp account and verify ownership of all sending domains. Here's the timeline: Starting 3/16, all new Mandrill users will create accounts through MailChimp, and current Mandrill users can merge their existing Mandrill account with a monthly MailChimp account. Current users will have until 4/27 to merge their accounts.

Reference: http://blog.mandrill.com/important-changes-to-mandrill.html