We are using Email Router for Dynamics CRM 2011. And we have lots of profiles there. During migration to CRM 2015 we need to recreate email server profiles and mailboxes. I don't like how OOB migrate email router data works. Cause it creates email server profile per email router configuration profile. I prefer create one email server profile per email provider (smtp server) and store credentials in mailboxes. It's more convenient. It was a bit time consuming to request email passwords from our clients. So I decided if email router can decrypt passwords, so should I. With this few PowerShell lines you can get passwords for your email profiles:
sl 'C:\Program Files\Microsoft Dynamics CRM\CRMWeb\bin>'
Add-Type -Path .\Microsoft.Xrm.Service.dll
Add-Type -Path .\Microsoft.Crm.dll
$enc = New-Object -TypeName Microsoft.Crm.Encryptor -ArgumentList 'C:\Program Files\Microsoft CRM Email\Service\EncryptionKey.xml'
Replace EncyptedEmailPassword with value between EmailPassword from Microsoft.Crm.Tool.EmailAgent.xml.