Whats new in Mailster 3.0?

We are happy to announce the release of Mailster 3.0. It was a long journey and an overdue update. We are really happy to bring you the latests and greats features to the ultimate email newsletter plugin.

Customers often facing problems when it comes to deliverability. In Mailster 3.0 we have focus to get your campaigns into your subscriber inboxes.

Test the Email Quality with the built in Pre-check Feature.

The new Pre-check Feature helps you find possible problems in your email campaigns before you hit the send button.

The Campaign Pre-check modal

The new pre-check feature will replace the campaign preview screen as well the spam score check. It will give you an score between 0 and 100 (where 100 is the best).

With a click of a button Mailster will check following things of your campaign:

campaign precheck results
Campaign Pre-Check Results


Find problems in your subject line or body copy. Count words and characters in your email as well the total email file size. There’s also an image-to-text ration which helps you to balance them.


Checks all used links in the campaign and if they are reachable or blocked.


Checks your used images if they are reachable on the internet and contain an alt tag for accessibility.

Spam Report

Gets you a SpamAssassin score which counts into your total score.


Checks several authentication methods for your current delivery set up like SPF, DKIM or DMARC. Also checks the A and MX records of your sender.

Blocklist (Blacklist)

Checks the IP of your sender against over 50 blacklist services.


We help you prevent false signups out of the box. It’s now more easy to block bots without an additional plugin.

settings security
Security Settings Page

With this new security settings Mailster makes it easy to help you prevent false signups and slo allow you to block certain domains or IP addresses.

We have redesigned our honeypot mechanism and incorporated an “anti-flood” mechanism to prevent multiple sign-ups in a given time frame.

Auto Batch Size Setting

While this sounds maybe a bit strange it’s exactly that: A setting to allow Mailster calculating the best send rate so your mails get out as fast as possible.

Check our article on the Knowledge base for more info on that.

PHP 8 Support

We have throughly test Mailster with PHP 8.0 and starting testing with 8.1. While the minimum required PHP version is still 5.3.6 it’s a good time to update your PHP version as we plan to increase the minimum PHP version in a future update..

New Templates and Add ons page.

Mailster supports a lot of templates and add-ons so we made it easier for you to find them and use them in your Email Marketing Software.


We are really happy with Mailster 3.0 and its foundation for your future email marketing platform.

The update is of course free for all licensee and available within the first week of September this year.

For anyone having issues or questions for this release we have extended your support to the end of September 2021.

By Xaver

Founder and creator of Mailster.


Is the blocked emails and domains only for email signups (can’t sign up for newsletter) or email sendings (if Mailster tries to send email to this address/domain it will not be sent) – or both?

It’s only for new contacts. Once in your database Mailster will use the email address no matter if a rule match.

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