Mailster – Email Newsletter Plugin for WordPress changelog

2026 5 versions

4.1.21 Latest 19 Oct 2026 1 new2 improved7 fixed

New

• Bulk actions to add or remove tags on the subscribers list

Improved

• Subscriber list tags and lists link to a filtered view of matching subscribers
• Tag assign APIs treat integers as tag IDs and strings as tag names — custom code must cast IDs with (int) (numeric strings like "42" are names, not IDs)

Fixed

• Retina loading spinner 404 when legacy form styles are printed inline
• All status filter count on subscribers screen showing 0
• Tags with numeric names (e.g. "2026") can be created and assigned
• Mailster_list_removed and mailster_tag_removed no longer run when the subscriber was not on that list or tag
• List-based unsubscribe still succeeds when the subscriber is not on every campaign list
• Image placeholder endpoint no longer allows unbounded image sizes
• Numeric custom date fields now keep date operators, formatted values, and export date formats

4.1.20 5 Oct 2026 7 fixed

Fixed

• Pasting URLs into module text links in the campaign editor on Firefox
• Backslash before apostrophe in sender name on delivery settings test email
• Accented characters in campaign email body are preserved when saving
• Campaign click links now check lookalike domains and keep percent signs in URLs
• Subscriber conditions and field deletes handle values more safely
• Subscriber import failing when first or last name is empty
• Several AJAX actions and subscriber imports now verify requests before running

4.1.19 21 Sep 2026 1 improved6 fixed

Improved

• Dependencies

Fixed

• Date and anniversary workflow triggers now apply custom-field offset when matching subscribers
• Block form preview no longer allows unauthenticated SQL injection via mailster-block-preview
• Campaign builder module titles and content with UTF-8 characters
• Subscriber export download now requires export capability and rejects unsafe filenames
• Template delete no longer allows path traversal outside the templates directory
• Block form placement preview scrolling no longer fails across origins

4.1.18 14 Jul 2026 2 improved2 fixed

Improved

• Anti-flood protection now uses the direct client IP instead of forwarded headers
• Dependencies

Fixed

• Template save and ZIP upload AJAX endpoints now block path traversal and unsafe file types
• Block form REST submissions no longer accept certain subscriber fields

4.1.17 9 Mar 2026 12 improved3 fixed2 removed1 changed

Improved

• Block forms now support block gaps.
• Block form message now visible in the editor.
• Block form message now supports borders and shadows.
• Buttons on campaign edit screen for WordPress 7.0.
• Visual fixes for WordPress 7.0.
• Quickly copy Block Markup for block forms (next to short codes).
• Sanitize URLs using esc_url() for improved security.
• Included form patterns for WordPress 7.0.
• Validate form ID by ensuring it is numeric before processing in frontpage class
• Replace ButtonGroup with Flex component in FormSelector and EmailSelector for improved layout consistency
• Included form patterns for WordPress 7.0.
• Dependencies

Fixed

• Missing conditions error on manage subscribers screen.
• Missing colors on forms if block messages have a non-default color.
• Form section in form blocks now displays all available forms when there are more than 10.

Removed

• Clean lists note on import screen.
• Deprecated utf8_* methods.

Changed

• This update brings stability and improvements for WordPress 7.0.

2025 8 versions

4.1.16 23 Dec 2025 2 improved1 fixed1 removed

Improved

• Ensure only the latest export file is downloadable by validating the filename against stored option
• Modify MIME type for zip uploads and enable type testing in MailsterAjax class

Fixed

• Broken blocks on automation by adding sprintf function to i18n imports for better string formatting in multiple files

Removed

• Eliminate remove_template method from MailsterAjax class to streamline AJAX functionality

4.1.15 2 Dec 2025 4 improved3 fixed

Improved

• Streamline form retrieval and fallback logic in MailsterNotification class for improved readability and maintainability
• Bump dependencies and lock files to latest versions for improved compatibility and performance
• Enhance URL validation logic in MailsterFrontpage class to include campaign status checks and improve error handling
• Add next40pxDefaultSize prop to various components for consistent styling across form elements

Fixed

• Correct logic in URL validation check
• Check if campaign is in a valid status before checking the content
• Missing sprintf on automation edit screen

4.1.14 21 Oct 2025 4 improved1 fixed

Improved

• Sanitize URLs in subscribers table class for improved security
• Update content filters and actions for better form rendering and modularity in block forms. Popups are now rendered inside the_content filter, which improves compatibility with more themes and core blocks, used inside the form.
• Bump dependencies and lock files to latest versions for improved compatibility and performance
• Correct typo in welcome message on campaigns dashboard

Fixed

• Synchronize max days for warmup settings between queue and delivery files

4.1.13 6 Oct 2025 1 new1 improved1 fixed

New

• Option to continue workflow on specific date delays if the date is in the past

Improved

• Dependencies and lock files for improved compatibility and performance

Fixed

• Css: issues with some themes on the automation editor

4.1.12 5 May 2025 1 fixed

Fixed

• Cast smtp_secure option to string for proper type handling

4.1.11 1 May 2025 4 new4 improved1 fixed1 changed

New

• Implement installation checks and enhance default settings handling
• Link to documentation for capabilities settings page
• New capability to delete campaigns with appropriate roles and help text
• New helpdesk links to the settings page

Improved

• Improve notification template fallback and error handling
• Improve SMTP configuration type casting
• Improve wp_mail filter argument handling
• Enhance import functionality and UI interactions

Fixed

• Correct parent block references for condition blocks

Changed

• Packages updates

4.1.10 10 Mar 2025 4 improved1 fixed

Improved

• Updated Dependencies and Package Versions
• Update commit message guidelines
• Improve form block error handling
• Refactor homepage block edit and inspector controls

Fixed

• Improve capabilities and permissions system

4.1.8 7 Jan 2025 1 improved1 fixed1 removed

Improved

• Updated packages

Fixed

• Bug when subscribe on multiple lists. 'wpdb->delete' may return 0 so do better checks

Removed

• Removed redundant shortcode

2013 1 version

4.1.9 10 Feb 2013 1 new2 improved2 fixed1 changed

New

• New capabilities delete_private_newsletters, delete_published_newsletters

Improved

• Alignment of elements in the automation inspector
• Use ToggleGroupControl on update custom field action for checkboxes

Fixed

• Missing capability to delete campaigns in some case
• Missing key in array function

Changed

• Package upgrades

2024 21 versions

4.1.7 17 Dec 2024 1 improved2 fixed

Improved

• Freemius SDK to 2.10.1

Fixed

• Issue where activating caused a fatal error if wp_mail is used by another plugin
• Typo

4.1.6 27 Nov 2024 1 new1 improved3 fixed1 removed1 changed

New

• 'nextHasNoMarginBottom' to components to prevent deprecated messages in WP 6.7

Improved

• Dependencies for composer and npm

Fixed

• Campaigns cache were not cleared on status change
• Condition using "have" and "doesn't have" tags returned wrong results
• Force boolean on some expressions

Removed

• Option to upgrade license from notification

Changed

• Less use of constant MAILSTER_BUILT

4.1.5 11 Nov 2024 1 new5 improved8 fixed1 removed1 changed

New

• {second} tag to display the current second

Improved

• Admin notices improvements
• Show "0" values on subscriber details page instead of nothing
• Convert license screen
• Option to quickly remove filter from subscriber overview
• Updated Freemius SDK to 2.9.0

Fixed

• Minor CSS issues
• PHP Notice while Autoresponder converting
• Trigger selector break blocks if connection is to slow
• Cache wasn't cleared for block forms in some cases
• Conditions with quotes are rendered incorrectly
• Form patterns were missing on saved block forms
• Race condition when a workflow is triggered on manual user update
• Searchmark causes error if applied on non strings

Removed

• Legacy usage tracking

Changed

• Rewritten notice methods

4.1.4 25 Sep 2024 2 improved2 fixed

Improved

• Checks if Mailster methods are called before Mailster is initialized
• Support for WooCommerce Add-on

Fixed

• Profile showed unsubscribe button
• Workflow can be triggered multiple times in some instances

4.1.3 16 Sep 2024 2 improved4 fixed

Improved

• Allow updating from the dashboard if translations have been loaded already
• Hook based triggers now support multiple or all subscribers

Fixed

• Automation schedule generated invalid query if empty arguments were passed
• Missing translations
• Respect WPLANG property when fetching translations
• Typo on dashboard

4.1.2 9 Aug 2024 1 new1 improved4 fixed

New

• Link to Translator Program on dashboard

Improved

• Form patterns are now translate-able

Fixed

• PHP warning in automations class
• Missing ID when block forms are used on the frontend
• Missing campaign on email workflow
• Some strings weren't translate-able improved: translations

4.1.1 5 Aug 2024 3 fixed

Fixed

• PHP Error with PHP version 7.4
• Jumper Step caused broken block in some cases
• Step Appender not aligned correctly

4.1.0 5 Aug 2024 10 new12 improved

New

• Jumper Step: Jump to a specific step in the workflow.
• Notifications Step: Send a notification to an email address.
• Allow Prefills forms with URL parameters.
• Queued subscribers on workflows can now get inspected and removed/forwarded/finished.
• Option to skip steps in workflows.
• Option to allow pending Subscribers entering the workflow.
• Option to activate/deactivate and duplicate the workflow from the overview page.
• Capabilities to manage workflows and block forms.
• Shortcode of forms is now quickly copyable from the forms overview page.
• Option to selected autocomplete type for input elements on forms.

Improved

• Initiation Mailster. Now the main class is loaded when all plugins are available.
• Newsletter Homepage in the Site editor is not broken anymore.
• Frontend script for forms is executed with domReady.
• BlockRecovery now uses less resources.
• Refetching data is now less resource intensive.
• Missing step appender in WP 6.6 is now back (and better).
• New icons for some steps to make them more distinguishable.
• Time related input fields got a "now" button to quickly jump to the current time.
• More option buttons in editor toolbar for better accessibility.
• Workflows can now run max 1024 steps in a single process to prevent infinite loops.
• Canvas toolbar is now located in the canvas.
• Wp_mail setup: changed the way functions are loaded

4.0.11 17 Jul 2024 4 fixed

Fixed

• PHP error "attempt to assign a property to an array"
• Styling issues on Automations with WP 6.6
• Missing Canvas tools on WP 6.6
• Workflow steps with delay didn't calculated the timezone correctly.

4.0.10 24 Jun 2024 2 improved2 fixed

Improved

• Css improvements
• Update plugin api info

Fixed

• Escaping on web version
• Subject placeholder tag in title was not replaced on the webversion

4.0.9 14 May 2024 1 improved9 fixed

Improved

• Bounce performances

Fixed

• Line height on form selector input field
• PHP Warning: preg_replace(): Compilation failed with certain shortcodes.
• PHP deprecated notice
• Admin header was visible on the newsletter homepage
• Deeplink of steps works again
• Dynamic properties are deprecated
• Fatal error on tags triggers if no tag has been set
• Logos were not applied to some templates
• Translation wasn't loaded before the setup wizard

4.0.8 26 Mar 2024 3 improved3 fixed2 removed2 changed

Improved

• Legacy forms inclusion
• Activation experience for Envato users
• Bounce handler to not timeout during processing of large quantities of bounce messages

Fixed

• Linked images in templates weren't mapped correctly.
• Missing array index in options.php
• Using "given-name" for autocomplete value instead of "name" on the first name field for block forms

Removed

• Beta notice
• Health check notice.

Changed

• Reverted: forcing unsubscribe link on the bottom of the mail if not present in the email.
• Fully tested with WordPress 6.5

4.0.7 11 Mar 2024 2 improved3 fixed1 removed

Improved

• Legacy forms inclusion
• Bounce handler to not timeout during processing of large quantities of bounce messages

Fixed

• Action links on campaign overview page.
• Linked images in templates weren't mapped correctly.
• Missing array index in options.php

Removed

• Deprecated cron trigger

4.0.5 23 Feb 2024 1 improved1 fixed

Improved

• Loading time on subscribers overview

Fixed

• SQL error on form preview page

4.0.4 21 Feb 2024 2 improved2 fixed

Improved

• Fast triggers in automations
• Cleanup on date related workflows

Fixed

• Journey were triggered more than once in some circumstances
• Usage of wp_posts instead of {$wpdb->posts} on some queries

4.0.3 20 Feb 2024 1 new1 fixed

New

• Upgrade notice

Fixed

• Small bug fixes and CSS improvements

4.0.2 16 Feb 2024 2 improved2 fixed

Improved

• Handling different translations for different users
• Included templates

Fixed

• Custom field creation during import if no custom fields are present
• Render error if first step in workflow is removed

4.0.1 14 Feb 2024 4 fixed

Fixed

• Some phpcbf issues
• Newsletter homepage creation causes broken blocks
• Checkout links fixed: typo
• Some automations got stuck on the delay step under certain conditions

4.0.0 12 Feb 2024 1 new13 improved2 fixed3 removed51 changed

New

• New filter 'mailster_cron_simple_output' to change the output of the cron page.

Improved

• Improved native support forms for Elementor, including a change in the slug of the Elementor module to prevent conflicts.
• Performance improvements on querying action data from campaigns and on data in the wp_options table.
• Honeypot mechanism to prevent false positives on heavily cached sites and improved to prevent false positives more broadly.
• Updated WP Coding Standards to 3.0.
• Improved preview of forms from the block form overview.
• Improved rewrite rules for newsletter homepage.
• Improved placeholder image tags algorithm.
• Improved beacon message loader.
• Freemius SDK updated to 2.6.2.
• Geo API: Updated to use preferred single mmdb file instead of multiple data files.
• Admin Screens: Improved rendering.
• Improved log cleanup algorithm.
• Support block form preview in the site editor.

Fixed

• General Fixes:
• Smaller fixes and improvements, cleanup.

Removed

• Deprecated:
• Deprecated notice on subscribers detail page for PHP 8.2+.
• Inline style attribute got removed in some edge cases.

Changed

• Email Health Check: Check your delivery method to comply with upcoming changes to Gmail and Yahoo.
• Block Forms: Create forms and popups with the built-in editor.
• Automations: Bring automations to the next stage with customer journeys.
• One Click Unsubscribe: Now enabled by default for Gmail and Yahoo, complying with RFC 8058.
• Save Custom Modules: Allows for saving and reusing custom modules within the platform.
• Native Support:
• For DIVI.
• General:
• Welcome Wizard.
• Automation triggers now run on the same process.
• List view labels are more descriptive.
• Newsletter homepage block.
• Standardized rendering of campaigns.
• Rendered of admin screens.
• Subscribers detail page.
• Allow any type of hook in hook triggers.
• Forms and Popups:
• Block form preview.
• Animations on forms are now reduced if clients use "prefer-reduced-motion".
• Compatibility and Standards:
• PHP 8.2 compatibility.
• Fully tested for PHP 8.1 and partially tested with PHP 8.2.
• UI/UX:
• CSS improvements on the form editor.
• General style updates.
• Technical and Structural:
• Page link triggers are now stored differently.
• No longer use trigger post meta value for automation triggers.
• Moved form padding to style section.
• Hide "Show form" option if used in content.
• Legacy forms.
• SDKs and Libraries:
• Warning on activation if update state is not clear.
• Warnings when trying to resize SVG images in email.
• Custom fields were not saved in some cases.
• Warning on PHP 8.2 if subscriber count is 0.
• CodeMirror editor not responding.
• Mailster_ip2Country didn't return country codes.
• Forms popup appear in wrong places.
• Conditions were sometimes wrongly not fulfilled.
• Automations don't get triggered due to a wrong db column.
• Scroll percentage trigger was not working.
• Align property hasn't been stored if forms are used out of context.
• Prevent step ID be the same if multiple blocks are duplicated.
• Premium Templates: Now available to certain plans.
• Specific Date and Anniversary Triggers: Can now have an offset.
• Support and Cleanup:
• Run KSES filter on form output via shortcode.
• Miscellaneous:
• Option to convert certain autoresponders to workflows.
• Legacy forms menu entry is hidden by default.

3.3.13 15 Jan 2024 1 new

New

• Email Health Check: check your delivery method to comply with upcoming changes to Gmail and Yahoo

3.3.12 10 Jan 2024 1 improved3 fixed

Improved

• Subscribers detail page

Fixed

• Deprecated notice on subscribers detail page for php 8.2+
• Warning on activation if update state is not clear
• Warnings when trying to resize SVG images in email

Undated 1 version

4.0.6 3 improved4 fixed

Improved

• Added option to define 'fields' in search query on the subscribers overview to search only within certain fields
• Deleted subscribers no longer count to totals on overview page
• Loading of lists page with large subscriber base.

Fixed

• Custom fields with underline were not working
• Check for array on bulk actions on campaigns
• Embeded elements were broken caused by block forms
• Wrong link in the block form overview

2023 4 versions

3.3.11 21 Nov 2023 3 fixed

Fixed

• Deprecated method
• Issue when replacing links introduced in 3.3.9
• BF sales dates

3.3.10 15 Nov 2023 3 fixed

Fixed

• Warning on PHP 8.2 if subscriber count is 0
• Issue with the admin bar
• Smaller issue

3.3.9 6 Nov 2023 3 improved2 fixed1 changed

Improved

• WP Coding Standards 3.0
• Freemius SDK to 2.6.0
• Placeholder image tags algorithmus

Fixed

• Inline style attribute got removed in some edge cases
• Smaller issue

Changed

• PHP 8.2 compatibility 🎉

3.3.8 5 Oct 2023 3 improved

Improved

• Honeypot mechanism to prevent false positives on heavy cached sites.
• Wording on support
• Freemius SDK to 2.5.12