API Bug Fix May 23, 2019

Important changes to the way we handle headers when sending with SMTP

On Monday, May 20th we made a change to the way we process SMTP headers for emails that are sent with SMTP. Please note that this change does not affect sending via the API.

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Historically, when Postmark accepted messages over SMTP, we have constructed the To, Cc, and Bcc headers for messages sent to show only the subset of recipients you specify during sending. In some uncommon cases, this behavior meant that not all recipients would be visible in the message that is delivered to your recipients.

With this update, we will ensure that the recipients that are visible in your messages’ To and Cc headers are the same as what will be shown to the final recipients of your messages. We will no longer reconstruct them based on our older behavior, which, in some uncommon cases, could have prevented some recipients from being displayed in the final email that we deliver.

Read the blog post for full details.

February, 2019

Starting March 7th our SMTP outbound servers will only support encrypted connections using TLS

We will disable support for SSL v3 on March 7th, and going forward our servers will only support encrypted SMTP connections using TLS (1.0 - 1.3). Most customers will not be affected by this change. However, you can double check that your SMTP client is compatible by temporarily sending mail through future-smtp.postmarkapp.com instead of smtp.postmarkapp.com.

future-smtp.postmarkapp.com points to the new servers (and new IPs) and it does not allow SSL v3 connections. If you use connection to test and everything works well, no further action is needed and sending should continue through our current endpoint: smtp.postmarkapp.com.

If you are having trouble connecting over future-smtp.postmarkapp.com you will need to update your SMTP client. Please can let us know if you are not able to resolve or update your SMTP client before the switchover date.

July, 2018

Version 2.6.0 of the official PHP library for Postmark

This release includes support for our new metadata feature. You may now include metadata with your outbound messages, and Postmark will include that data in webhook payloads, message details, and message searches. See the full release announcement here.

This release also enables you to specify the BaseURL for each API request, making testing with Guzzle a lot easier.

Finally, you can now enable, or disable SMTP API Error Webhooks for Servers using the Admin Client.

As always, we hope this release helps you get even more value from Postmark, and please feel free to contact us if you have any questions or requests!

Updates to the Swiftmailer Transport for Postmark

Our Swiftmailer Transport for Postmark has been updated with some minor enhancements, and it also now works with SwiftMailer 6.

Postmark official .net client updated to v3.3.0

This release of the official .net client for Postmark includes the addition of the Domains APIs, support for our new custom metadata feature, as well as the “EnableSMTPErrorHook” property to the the Create and Edit Server endpoint methods.

Custom metadata for your emails

You can now add custom metadata to your emails, and we'll pass that same data back to your system through our webhooks.

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For more details on how to implement and use this feature, check out the announcement blog post, help documentation as well as our updated developer documentation.

March, 2018

Modular webhooks

You can now add multiple webhook URLs for a server and choose which events you’d like to send to each specified URL.

December, 2016

Webhook for delivery events

Postmark can now notify your application of delivery events via webhooks so you can do a variety of things like feed delivery events into an internal system, provide delivery even notifications to your customers, or aggregate delivery even data to see patterns and respond accordingly.