Next update for GD Mail Queue Pro plugin, version 4.1 has been just released, and it includes several updates and fixes, support for MailJet SMTP service and two new REST API addons: Gmail and MailJet.
The plugin has new SMTP service built in, this time for MailJet with options to control tracking. Besides that, the plugin has a new way for detection of plain text emails. In some cases, if the wp_mail is used incorrectly to build HTML email, the plugin can wrongly detect the type of email. These changes solve that problem. You have new advanced misc settings to control the detection process and to if needed, fix the wrong content type.
This version improves on few things, and it also fixes several bugs including SendGrid missing ReplyTo value, some minor issues with base addon classes and potential issue with saving error message in the log.
The plugin has two new addons, for two very popular email services: MailJet and Gmail. For Gmail, there is a comprehensive user guide included with information on how to set the API access (and it is not simple, considering how complex API system Google has). The plugin now supports 5 third-party services using the REST API connection methods.
Check out the plugin features, and let me know what else would you like to see in the plugin and which third-party services to support. If you find any issue with the plugin, as usual, please report them in the support forums.