MC4WP: Mailchimp for WordPress

• Fix JS error breaking Ninja Forms edit form page when not connected to a Mailchimp account or account has no audiences.
• Remove sprintf usage in hot path.
• Lazy load MC4WP_API_V3 class to save some memory and parse time.
• Save a tiny bit of memory in autoloader implementation by not repeatedly storing plugin directory.
• Remove unused setting key from default options.

• Bump required PHP version to 7.4 or higher.
• Obfuscate API key the same way as in the Mailchimp.com interface.
• Delete all plugin data when plugin is uninstalled / deleted via WP Admin.
• Fix several PHP 8.4 deprecation warnings.
• Address warning about translations being loaded too early if using Ninja Forms integration.
• Run stored setting values related to user-facing textual messages through i18n functions to allow translating them through plugins like Loco Translate or WPML.

• [Forms] Rename "list choice" to "audience choice" in available form fields.
• [Ninja Forms] Fix gettext being called too early warning in Ninja Forms base class.
• [WooCommerce] Allow pre-checking of sign-up checkbox in Checkout Block.

• Add integration with Prosopo, a GDPR compliant anti-spam solution for protecting your sign-up forms against bot sign-ups. Thanks Maxim Akimov!

• Bump required PHP version to 7.2.
• Prevent non-functional checkbox from showing up on WooCommerce my account page if WooCommerce checkout integration is enabled.
• Update default form content to include a "for" attribute on the label element.
• Minor performance optimizations to MC4WP_Form::get_subscriber_tags()
• Begrudgingly rename Mailchimp lists to Mailchimp audiences throughout the plugin's admin interfaces.

• Fix compatibility with WooCommerce versions 8.5 to 8.8 because of private method that was later made public.
• Fix potential reflected XSS by stripping and escaping all HTML from {email} tag replacements. Thanks to kauenavarro for responsibly disclosing.
• Fix potential stored XSS for attackers with both administrator access and Mailchimp account access by escaping HTML from interest group name. Thanks to Jorge Diaz (ddiax) for responsibly disclosing.

• Add support for WooCommerce Checkout Block in sign-up checkbox integration.

• Improved anti-spam measures on the custom form integration. If you are using the custom form integration (using the mc4wp-subscribe checkbox), please test your forms after upgrading and report any issues to us.
• Improved anti-spam measures on all sign-up forms.
• Remove unsupported filter hook from Gravity Forms integration.

• Very minor code-size improvements to public forms related JavaScript.
• Update third-party JS dependencies.
• Bump tested WordPress version to 6.6.

• Fix last 10 Mailchimp lists not being pulled-in when having more than 10 lists.

• Update third-party JS dependencies.
• Bump tested WordPress version.

• Integrations: Update CheckoutWC hook name for WooCommerce checkbox integration.
• Forms: Don't show form preview to users without edit_posts capability.
• Forms: Explicitly exclude form preview from search engine indexing.
• General: Don't unnecessarily go through service contrainer while bootstrapping plugin.
• General: Remove some unnecessary JavaScript now that browser support has caught up.

• Fix class "MC4WP_Usage_Tracking" not found error for WP Cron / WP CLI processes.

• Remove the opt-in usage tracking functionality as we're not really using it for decision making anymore.
• Add missing label element to the select element for setting the logging level.
• Our JavaScript assets are now transpiled to support the same set of browsers as WordPress core. This drops support for some very old browsers, but results in smaller bundle sizes for the supported set of browsers.
• Update third-party JS dependencies to their latest versions.

• Update third-party JS dependencies.
• Minor textual improvements.
• Bump tested WordPress version.

• Update third-party JS dependencies.
• Address some minor codestyle issues.

• Fix generated HTML for list/audience choice fields.
• Fix deprecation warning in includes/admin/class-review-notice.php.
• Update JavaScript dependencies.

• Fallback to default checkbox label if none given. Thanks to Shojib Khan.
• Improve WooCommerce integration settings page by disabling position field if integration is disabled. Thanks to Shojib Khan.
• Update JavaScript dependencies.

• Defend against breaking change in latest WPForms update.

• Add support for a field named MARKETING_PERMISSIONS to enable GDPR fields configured in Mailchimp. A sample code snippet can be found here.
• Remove Google reCaptcha feature. This was already disabled if you were not already using it.

• Fix generated value attribute for fields of type choice (dropdown, checkboxes, radio fields).
• Fix type of marketing_permissions field in API requests. Thanks to George Korakas.
• Refactor list overview JS to not depend on Mithril.js anymore.
• Simplify admin footer text asking for a plugin review.
• When renewing lists, renew cached marketing permissions too.

• Removed deprecated filter hook mc4wp_settings_cap, use mc4wp_admin_required_capability instead.
• Removed deprecated filter hook mc4wp_merge_vars, use mc4wp_form_data or mc4wp_integration_data instead.
• Removed deprecated filter hook mc4wp_form_merge_vars, use mc4wp_form_data instead.
• Removed deprecated filter hook mc4wp_integration_merge_vars, use mc4wp_integration_data instead.
• Removed deprecated filter hook mc4wp_valid_form_request, use mc4wp_form_errors instead.
• Removed deprecated function mc4wp_get_api() and deprecated class MC4WP_API.
• Removed deprecated function mc4wp_checkbox().
• Removed deprecated function mc4wp_form(), use mc4wp_show_form() instead.
• Added filter mc4wp_debug_log_message to modify or disable messages that are written to the debug log.
• Fix color of invalid Mailchimp API key notice.
• Sanitize IP address value from $_SERVER['REMOTE_ADDR'] too.
• Fetch GDPR marketing permissions via first subscriber on list and show them in lists overview table.

• Minor performance, memory usage & size optimizations for all JavaScript code bundled with this plugin.

• Improved default styling for the WooCommerce sign-up checkbox integration.
• Add <strong> to allowed HTML elements for GDPR disclaimer text on settings pages.
• Remove all references to obsolete placeholders.js polyfill.
• Move the GiveWP sign-up checkbox closer to the email input field. Thanks Matthew Lewis.

• Fix mc4wp_get_request_ip_address() to return an IP address that matches Mailchimp's validation format when X-Forwarded-For header contains a port component.

• Fix mc4wp_get_request_ip_address() to pass new Mailchimp validation format. This fixes the "This value is not a valid IP." error some users using a proxy may have been seeing.

• Fix PHP 8.1 deprecation warnings in MC4WP_Container class.
• Fix name of action hook that fires before Mailchimp settings rows are displayed on the settings page. Thanks LoonSongSoftware.
• Improve WPML compatibility. Thanks Sumit Singh.
• Fix deprecated function for AMP integration.
• Only allow unfiltered HTML if user has unfiltered_html capability. Please read the below.

Despite extensive testing, we may have missed some more obscure HTML elements or attributes from our whitelist. If you notice that some of your form HTML is stripped after saving your form, please get in touch with our support team and provide the HTML you attempted to save.

• Add nonce field to button for dismissing notice asking for plugin review.
• Add strings from config/ directory to POT file.
• Add nonce check to AJAX endpoint for refreshing cached Mailchimp lists.
• Add capability check to AJAX endpoint for retrieving list details.
• Schedule event to refresh cached Mailchimp list upon plugin activation.

Thanks to the team over at pluginvulnerabilities.com for bringing some of these changes to our attention.

Add nonce verification to all URL's using _mc4wp_action query parameter. This fixes a CSRF vulnerability where a malicious website could trick a logged-in admin user in performing unwanted actions.

A special thanks to Erwan from WPScan for bringing this issue to our attention.

• Add defer attribute to JS file, so page parsing isn't blocked at all.
• Rewrite plugin CSS to optimize for selector performance and get rid of some duplication.

After installing this update, make sure to also update any add-on plugins like Mailchimp for WordPress Premium and Mailchimp Top Bar.

• Fix fatal error on older PHP versions when submitting form without any subscriber tags set in the form settings.
• Minor performance improvement in bootstrap method of the plugin.

• Allow short-circuiting mc4wp_subscriber_data filter by returning null or false.
• Use a subdirectory for the default debug log file location, so that it's easier to protect using htaccess.
• Improved reliability for fetching lists from mailchimp when lists have high stats.member_count property.

• Fix notice by explicitly setting permission_callback on registered REST route.
• Minor internal code improvements.

• Plugin now requires PHP 5.3 or higher.
• Prefix overlay classname to prevent styling collissions with other plugins.
• Form sign-ups can now add tags to both new and existing subscribers.
• Update JavaScript dependencies.
• Register script early to work with Gutenberg preview.

• Add MC4WP_API_V3::add_template method.
• Minor code hardening to ensure a default form is always set.
• Update JS dependencies to their latest versions.
• Fix icon for Gutenberg block.

• Update JS dependencies to their latest versions.
• API client add_list_member method now has an additional parameter to skip merge field validation.
• Simplify code for updating an existing form.

• Update JS dependencies to their latest versions.
• Check if className is of type string, fixes a console warning when clicking inside a SVG element.
• Minor improvements to the AMP implementation to address harmless validation warnings.

• Add AMP compatibility to sign-up forms, thanks to Claudiu Lodromanean. This uses the official AMP plugin for WordPress.
• Add settings key to WPML config so settings can easily by copied over to translated versions of a form.
• Optimize size & performance of JavaScript code, resulting in a file that is 40% smaller.
• Update CodeMirror to its latest version.
• Escape all string translations.

Fixes

• htaccess config for servers running Apache 2.4 or later.

Fixes

• Top Bar & User Sync add-on using API v2 since version 4.7.1.
• Revert change in formatter for date fields, breaking all forms with date fields in them.

Improvements

• Add getter method for raw (unmodified) data on form class.

Fixes

• Invalid .htaccess file in case there already is one in the uploads directory.

Improvements

• Update MemberPress hook names. Thanks Ian Heggaton!
• Use WordPress.org translations instead of bundling translation files in plugin itself.
• Write .htaccess to directory of debug log file, to prevent file access.
• Add some convenient hooks for Checkout for WooCommerce.
• Stop parsing shortcodes in text widgets as WordPress core does this since version 4.9.

Improvements

• Add role=alert to form notices.
• Add setting to pre-check sign-up checkbox for Gravity Forms integrations.
• Add new position for WooCommerce integration: directly after the billing_email field.
• Fix PHP notices for submitting a form and saving a form as an administrator.
• Add link to Koko Analytics plugin.

Fixes

• Address fields in forms would always be required (even if really optional).

Improvements

• Add proper SVG admin menu icon.
• Minor overall performance and memory usage improvements.

Fixes

• Fixed list cache usage for WPForms, Gravity Forms and Ninja Forms integrations.

Improvements

• Improved fetch and cache mechanism for retrieving Mailchimp account details, fetching data only when it is required.
• Updated Mithril and CodeMirror dependencies.
• Decreased size of forms.js from 22KB to 9KB.
• No longer requiring jQuery anywhere.
• Increase API HTTP request timeout to 15 seconds.

Please note that installing this update requires you to also update any add-ons like Mailchimp Top Bar and Mailchimp for WordPress Premium (if installed).

Fixes

• Google reCAPTCHA script was still loading even if no forms have it enabled.

Improvements

• Removed custom color from menu item for improved accessibility.
• Take birthday field format into account when sending data to Mailchimp.
• Print Google reCAPTCHA script in footer.

Changes

• Changed plugin name to MC4WP instead of Mailchimp for WordPress.

Fixes

• Temporarily switch status of pending subscribers to "unsubscribe" versus deleting susbcriber before re-subscribing.
• Deprecation notice for Gravity Forms version 2.4 and higher.

Improvements

• Filter out empty tags when applying tags to new subscribers.
• Show all not installed integrations.
• Show notice when form doesn't have a Mailchimp list selected to subscribe people to.
• Check function existence for compatibility with WordPress 4.7
• Don't submit form when Google reCAPTCHA is enabled but errors.
• Update third-party JavaScript dependencies.

Improvements

• Accept more truthy values in custom integration for improved compatibility with third-party forms.
• Update JavaScript dependencies.
• Load Google reCaptcha script in footer (if needed).

Additions

• Add sign-up integration for Give
• Add sign-up integration for UltimateMember

Improvements

• Write to debug log if Google reCAPTCHA secret key is incorrect.
• Validate reCAPTCHA keys when savings form settings.
• Allow setting an empty "successfully subscribed" message.

Additions

• Built-in integration with Google reCAPTCHA to prevent bots from subscribing to your Mailchimp lists.

Improvements

• Minor improvements to the JavaScript that is loaded on admin pages.

Fixes

• AffiliateWP integration subscribing the wrong user if affiliate ID differs from user ID.

Improvements

• Renamed "MailChimp" to "Mailchimp" to match Mailchimp's new branding.
• More accurate handling of timeouts for accounts with many MailChimp lists.
• UX improvements for integrations overview page.
• Validate MailChimp API key format when it's entered.
• Improved compatibility with Klarna Checkout in the WooCommerce checkout integration.
• Bumped required PHP version to 5.3 (soft requirement for now).

Additions

• Added Gutenberg block for easily adding a form to a post or page.
• Added subscriber tags setting to forms.

Fixes

• Update WPForms integration to properly detect if the WPForms plugin is activated.

Improvements

• Write API request parameters to the debug log in case of connection timeouts.
• Update JavaScript dependencies.

Fixes

• Use of readonly function, which is only available in WordPress 4.9 or later.

Fixes

• Fatal error on PHP versions older than 5.5

Additions

• Added MC4WP_API_KEY PHP constant which can be used to set your Mailchimp API key.
• Add mc4wp_mailchimp_list_limit filter hook to modify the maximum number of Mailchimp lists to fetch. Defaults to 200.

Improvements

• Apply mc4wp_integration_gravity-forms_options filter hook on Gravity Forms integration options so the checkbox can be prechecked and the checkbox label text modified.
• The updated_subscriber JS event is now fired forms not using AJAX as well (when applicable).

Improvements

• Only re-add subscriber to list if we want to re-trigger a double opt-in confirmation email.
• Change Gravity Forms field name to "Mailchimp for WordPress"
• Get rid of cached result of Mailchimp API connection.

Improvements

• Ensure type-safety on some global variables.
• Stop showing trashed forms immediately.
• Pre-check Mailchimp list when creating a new form if there is only 1 list.
• Send null for unknown values in usage tracking data (only when opted-in).

Additions

• Add methods for accessing Mailchimp's e-commerce promo code endpoints to API class.

Fixes

• Don't wrap "agree to terms" input in hyperlink element.
• Allow [ENTER] key again after field helper overlay is closed.

Improvements

• Fallback to meta-refresh if redirect fails because of "headers already sent" error.

Fixes

• Events Manager integration was not working with logged-in users.
• Form preview URL should respect admin HTTP(S) scheme.
• Removed use of PHP 5.4 function.

Improvements

• Add "agree to terms" checkbox to field helper.

Additions

• Add filter mc4wp_http_request_args.

Fixes

• Namespace usage warning when running PHP 5.2

Improvements

• Remove obsolete type attribute from all <script> tags printed by the plugin.
• Improved tooltips on settings pages.
• Do not pre-check integration checkboxes by default.
• Add textual warnings to settings that may affect GDPR compliance.
• Update translation files.

Additions

• Live form preview while editing form.

Improvements

• Improved conditional fields logic.
• Debug log now includes request & response data.
• Form JavaScript events are fired in an isolated thread now, to prevent errors in event callbacks from breaking form functionality.
• Don't send empty field values to Mailchimp when updating subscribers.
• Show interest grouping ID in list overview on settings page.

Fixes

• Ninja Forms export checkbox would always state "checked" when form contained a Mailchimp sign-up checkbox.

Fixes

• Dropdown fields with special characters were not properly passed to Mailchimp.
• Interest groups with an all-numeric ID were not properly passed to Mailchimp.

Improvements

• Various minor code optimizations
• Do not redirect when showing "already subscribed" warning.
• Improved scroll to form handling after a form is submitted without AJAX.

Fixes

• Validate method was incorrectly checking required array fields.

Improvements

• Wrap some missing strings in translate calls. Thanks morlor.
• Make it clear that redirecting after successful form submissions will not show the "subscribed" message.

Fixes

• Array to string conversion in default form messages.

Additions

• Allow marking Gravity Forms sign-up checkbox as a required field.

Fixes

• Ninja Forms double opt-in setting was incorrectly inversed.

Improvements

• Simplified form processing & notice logic.
• Prevent 404 errors by proactively replacing lowercased name="name" input attributes.
• Updated JavaScript dependencies.

Additions

• Integration for AffiliateWP.

Fixes

• Filter out empty array values when overriding selected Mailchimp lists via _mc4wp_lists.

Improvements

• Updated JavaScript dependencies.

Additions

• Link to the HTML Forms from the plugin settings pages.

Improvements

• Remove unused options from Ninja Forms integration.
• Now logging all sign-ups from Ninja Forms integrations when using Mailchimp for WordPress Premium.

Additions

• Added Gravity Forms integration. You can now integrate with Gravity Forms by adding the "Mailchimp" field to your forms.

Improvements

• Add <label> element to sign-up checkbox for WCAG compatibility.
• Custom integration now works with Enfold theme's contact form element.

Fixes

• Properly escape the return value of add_query_arg when it is used in HTML attributes to prevent cross-site scripting. Thanks to Karim Ouerghemmi of RIPS for responsibly disclosing.
• Now loading integrations after WPML so that String Translations work properly.

Additions

• Add sign-up integration for WPForms forms.

Improvements

• Updated internal JS dependencies.
• Form tag {data key="foo.bar"} now allows you to access nested array values.

Fixes

• Method on API class for retrieving campaign data.

Improvements

• Show Akamai reference number when an API request is blocked by Mailchimp's firewall.
• Minor output buffering improvements in form previewer.

Fixes

• Failsafe against outputting sign-up checkbox twice in registration forms.
• Properly close HTML anchor element in French translation files.
• Fix BuddyPress sign-ups when using WordPress Multisite.

Improvements

• Fire action hook mc4wp_form_updated_subscriber whenever a form was used to update a subscriber in Mailchimp.
• Increase browser timeout for AJAX request when fetching Mailchimp lists.

Additions

• Added campaign & template methods to API client class.

Fixes

• Some form specific JS events were not firing due to incorrect event names.
• Registration form integration now works with WooCommerce registration form.
• Notice that asks for a plugin review would re-appear after dismissing it.

Improvements

• Randomise time of cron event that renews Mailchimp lists.
• Always try to show Mailchimp list info when API key is given.

Fixes

• Use earlier hook priority for Ninja Forms 3 integration so action is registered on time.

Improvements

• Improved Mailchimp list fetching & memory usage for accounts with many lists.
• Show error message when fetching lists fails.
• Updated plugin translations.

Fixes

• WPML String Translation not working with the checkbox label for sign-up integrations.

Improvements

• Use updated order methods when using WooCommerce 3.0, thanks to Liam McArthur.
• Updated JavaScript dependencies.

Improvements

• Updated all JavaScript dependencies in the plugin.
• Failsafed filter hooks to prevent invalid variable types.
• Explain that greyed out integrations means that specific plugin is not activated.
• Conditional form elements now uses event delegation, so it works with forms in Boxzilla pop-ups.
• Updated language files.

Additions

• Added support for Ninja Forms 3.
• Added mc4wp_integration_show_checkbox filter.

Improvements

• Ensure fields are HTML decoded before sending to Mailchimp.
• Better OptimizePress compatibility.
• Show all address-type fields as required when form contains 1 or more fields of the same address group.

Fixes

• Don't call stripslashes on POST data twice.

Improvements

• Plugin review notice is now dismissible over AJAX.
• Improved formatting of birthday fields.
• Updated Polish translations, thanks to Mateusz Lomber.
• Updated German translations, thanks to Sven de Vries.

Additions

• Add update_ecommerce_store_product method to API class.
• Throw form specific JavaScript events, like 15.subscribed to hook into "subscribed" events for form with ID 15.

Fixes

• Unescaped request variable on integration settings page, allowing for authenticated XSS. Thanks to dxwsecurity for responsibly disclosing.

Improvements

• Add $args parameter to API::get_lists_activity method. Relates to the Mailchimp Activity plugin.

Improvements

• You can now enable or disable debug logging from the "Other" settings page.
• No longer using deprecated function in Contact Form 7, thanks to stodorovic.
• Improved UI for adding hidden interest groupings fields to a form.

Fixes

• Issue with escaped HTML when using form tags introduced by previous update.

Improvements

• Improved handling of large debug logs.
• Improved error messages when writing exceptions to debug log.
• Show notice when form is missing required Mailchimp fields.
• Custom form integration now handles arrays with 1-level depth. Thanks to Mardari Igor.
• You can now use nested tags in your form code, eg {data key="utm_source" default="{current_path}"}

Additions

• Add data-hide-if attribute logic to forms. See conditionally hide form fields. Thanks to Kurt Zenisek.
• Add hooks for delayed BuddyPress sign-up. Thanks to Christian Wach.

Improvements

• Obfuscate all email addresses in debug log. Thanks Sauli Lepola.
• Ask for confirmation before disabling double opt-in, which we do not recommend.
• Allow vertical resizing of debug log.
• Failsafe against including JavaScript file twice.
• No longer wrapping CF7 checkbox in paragraph tags.

Additions

• Added mc4wp_form_api_error action hook for API errors encountered by forms.
• Added element_class argument to [mc4wp_form] shortcode for adding CSS classes.

Fixes

• Issue with lists not showing when using W3 Total Cache with APCu object cache enabled.

Improvements

• We're no longer stripping newlines from text fields.

Additions

• Added missing e-commerce related API methods to API class.

Fixes

• Allow checkbox option for the List Choice field (again).

Improvements

• Fetch Mailchimp lists over AJAX, to speed up perceived performance (especially when your account has many lists).
• Periodically fetch Mailchimp lists, so cache is always fresh.
• Improved <label> element accessibility for checkbox integrations.
• Stop using double underscore prefix in function names, as these are reserved in PHP 7.
• {post} and {user} shortcodes now accept a default parameter.

Additions

• Add MemberPress integration.
• Add missing e-commerce related API methods for next week's WooCommerce Mailchimp e-commerce integration release.

Improvements

• Allow re-running previous migrations by visiting a certain admin URL.
• Do not show checkboxes option for fields that only accept a single value.
• Write field specific errors to debug log when Mailchimp denies a sign-up request.
• Write to debug log when custom integrations can not find an EMAIL field.
• Differentiate between connection & authorization errors when testing connection to Mailchimp.
• Bump limit of number of Mailchimp lists to fetch from 100 to 500.

Fixes

• Ninja Forms integration not working when using PayPal integration.

Improvements

• Show connection errors on Mailchimp settings page.

Additions

• Add pre-checked option to Ninja Forms integration.
• You can now conditionally hide fields or elements using the data-show-if attribute.

Fixes

• Hidden fields which referenced interest groups by name were not sent to Mailchimp.
• Adding hidden field to form would reset value on every change.

Improvements

• Decrease file size of JavaScript for forms by about 30%.

This release updates the plugin to version 3 of the Mailchimp API. Please read through the upgrade guide before updating to make sure things keep working as expected for you.

Changes

• "Send welcome email" is now handled from your list settings in Mailchimp.
• Filter mc4wp_form_merge_vars is now called mc4wp_form_data.
• Filter mc4wp_integration_merge_vars is now called mc4wp_integration_data.
• New format for GROUPING fields in forms & filter hooks.
• Value delimiter in hidden fields is now a pipe | character.

Additions

• New filter: mc4wp_form_subscriber_data.
• New filter: mc4wp_integration_subscriber_data.
• New form tag: {cookie name="mycookie"}

Improvements

• The plugin now communicates with the latest & greatest Mailchimp API.
• Previously unsubscribed subscribers can now be re-added without errors.
• Add User-Agent header to all API requests.
• Available fields in form editor are now split-up by category.
• Birthday fields now accept a broader range of values and delimiters.

Fixes

• Issue with only 10 Mailchimp lists / fields / interests being returned.
• Incorrect form message showing when double opt-in is disabled.
• Error in upgrade routine when API request fails.
• List fields not fetched when list has just 1 non-default merge field.

Improvements

• Smarter scrolling after submitting form & reloading page.
• Format output of {subscriber_count} tag.
• You can now use <img> in your form messages.
• Add Mailchimp API error code to debug log lines.
• Add plugin name + version to User-Agent header for all Mailchimp API requests.
• Make sure value of MC_LANGUAGE field is limited to 2 characters.

Improvements

• Update JavaScript dependencies for admin screens.
• Test debug log & show notice when it's not writable.

Additions

• Add "placeholder" option for dropdown fields.

Fixes

• Styles Builder in Premium not building because of incorrect flag in core plugin.

Improvements

• Don't show position option for WooCommerce integration when sign-up is implicit.
• Improvements to form previewer logic.
• Make sure admin notifications are always shown exactly one time.

Fixes

• Placeholder polyfill wasn't loaded (only in IE8 and below).

Improvements

• Don't write to debug log if it is not writable.
• Reset some CSS properties for commonly used class names in Form Editor & Debug Log.
• Do not unnecessarily register styles which are then immediately enqueued.

Additions

• Add "is required field" option for dropdown & radio fields in Field Helper.
• Link to Boxzilla plugin from admin sidebar.

Fixes

• Form Preview mode replaced all titles on that page with "Form Preview".
• API class fix for eCommerce360 functionality.

Improvements

• Show dismissible notice when API key is not set.
• Show empty API key errors in plugin log.
• Friendlier error message for re-subscribe failures.

Additions

• Add form.reset() method to JS API.

Fixes

• Shortcode wasn't accepting element_id as a valid attribute.
• Take array style fields into account when checking if a form contains a given field.

Improvements

• Nested fields will now be properly validated when they're marked as required.
• If plugin is installed using Composer, autoloader won't be loaded (again).

Fixes

• Form event for starting a form was named start where it should have been started.

Improvements

• Some preparations for the upcoming migration to the new Mailchimp API (version 3).
• Consistent hook parameters for mc4wp_form_subscribed action.
• Improved logic for rendering form response.

Additions

• New checkbox position for WooCommerce checkout integration.

Fixes

• Response message was shown for unsubmitted forms when using {response} in the form mark-up with multiple forms on the same page.

Improvements

• Scroll to form after form submission now uses native browser method scrollIntoView().
• Various improvements for right-to-left (RTL) sites.
• The Mailchimp API key is now obfuscated on the settings page.
• Contact Form 7 integration now uses an early hook priority to ensure we run before any page redirects.

Additions

• Add position option for WooCommerce integration.
• Add {post} tag whch can be used in form mark-up to fetch properties of the current page or post.

Fixes

• Forms with address fields never passing validation.

Improvements

• Perform type checks on global variables to prevent issues with poorly coded plugins.
• Add Interest Category ID to list overview table for easier debugging.
• Updated Russian translations.

Fixes

• Issue with API array responses (for the Mailchimp Activity add-on, for example).

Improvements

• Updated Dutch, Portugese, Spanish and Italian translations.

Fixes

• Form JavaScript not working when another plugins loads Dojo framework.
• [ENTER] not submitting form settings or creating new-line.
• Internal fields marked as required not passing form validation.
• Deselecting all Mailchimp lists wouldn't persist after saving form settings.
• No sign-up request firing for lists with only an EMAIL field.

Improvements

• Show accepted choice values for dropdown and radio fields in lists overview.
• Use all Mailchimp lists for Lists Choice field, instead of just the selected ones.
• Failsafed JavaScript for when any other script loads RequireJS globally.

Additions

• Added support for Shortcake plugin.
• Error message for when no list is selected can now be customized from the form message settings.

Fixes

• Field Helper not adding type attribute when building forms.
• Field Helper not setting the correct value attribute for Hidden Groups.

Improvements

• Add sourcemaps to minified JavaScript files.
• Add link to article on how to enable debug logging.
• Field Helper now always shows both placeholder and value fields.

Fixes

• <input> fields being stripped from form when saving as a role other than "superadmin" on MultiSite installations.
• Certain actions like "renew lists" not working for users other than admin (if they have explicit access to settings pages).

Improvements

• Show Akamai firewall reference number when site's IP address is blocked
• Make sure integrations have a Mailchimp list selected before trying to subscribe.
• Move less important settings to "Other" page.
• When a field is required in Mailchimp, it has to be required in forms as well now.
• Allow including a _mc4wp_email_type field in forms to set an explicit email type.
• Miscellaneous overall performance improvements.

Additions

• Added debug logging, which shows all warnings & errors the plugin encountered in communicating with Mailchimp.
• Add get_lists_for_email( $email ) method to API class.
• Add MC4WP_Queue class for better background processing of expensive operations.

Fixes

• Incorrect hooks being fired for successful and unsuccessful form sign-ups (which also broke the success redirect).

Improvements

• Allow splitting up "birthday" and "date" fields into separate fields with day, month and year index.
• Improved algorithm for finding fields when integrating with Contact Form 7 or other custom forms.
• Ninja Forms integration can now automatically find name-fields.
• Ninja Forms integration can now use mc4wp- prefixed admin labels.

Additions

• add_ecommerce_order() and delete_ecommerce_order() methods to API class.

Fixes

• 500 server error for "already subscribed" on Windows servers.
• Incorrect HTML being generated for hidden fields.
• Duplicate sign-up request when using CF7 integration.

Improvements

• Stop logging "already subscribed" errors to PHP's error log.
• Simplify pattern attribute for date fields.
• Remove invalid autofill attribute from honeypot field.

Fixes

Not being able to select a list when creating a new form.

Fixes

• Make sure mc4wp_show_form() works without passing a form ID.

Improvements

• Remove UI for bulk-enabling integrations, as every integration needs specific settings anyway.
• Do not print inline JavaScript for forms until it's surely needed.
• Add position key to mc4wp_admin_menu_items filter to set a menu position.
• Various minor code improvements.

Fixes

Workaround for SSL certification bug in WordPress 4.4, affecting servers with an older versions of OpenSSL installed.

Additions

Added mc4wp_use_sslverify filter to disable or explicitly enable SSL certificate verification.

Fixes

• Fixes compatibility issues with add-on plugins performing validation, like Goodbye Captcha and BWS Captcha.

Improvements

• Now using group ID's for interest grouping fields, so changing the group in Mailchimp does not require updating your form code.
• Never load enabled integrations which are not installed.
• Reintroduce support for automatically sending OPTIN_IP

Additions

• Add filter: mc4wp_form_data, filters form data before it is processed.

Fixes

• Added backwards compatibility for Goodbye Captcha integration.

Improvements

• Prevented notice when saving Form widget settings for the first time.
• Add autofill="off" to honeypot field.
• Remove nonces from forms as they're not really useful for publicly available features.
• Errors returned by Mailchimp are now logged for Forms as well.
• Pre-select Mailchimp list if there's just one list in the connected account.
• Added missing translation calls for Form Editor.

Fixes

• Redirect on success not working.
• Forms overview page redirected to main WP Admin page (edge case).
• Safari was always showing the leave-page confirmation dialog.

Improvements

• Add form-specific classes to preview form element. This allows the Styles Builder to work with the Form Preview.
• Form events are now triggered after the page has finished loading, so all scripts are loaded & ready to use.
• Reset background-color in Form Themes stylesheets.

Version 3.0 is a total revamp of the plugin. For a quick overview of the changes, please read this post on our blog.

Before upgrading, please go through the upgrade guide as some things have changed.

Breaking Changes

• Captcha fields: {captcha} field is now handled by the Captcha add-on plugin.
• New dynamic content tags syntax: {data_NAME} is now {data key="NAME"}
• Event binding: jQuery(document).on('subscribe.mc4wp','.mc4wp-form', function(){ ... }) is now mc4wp.forms.on('subscribed', function(form) { ... })
• Removed integrations: MultiSite & bbPress.

Improvements

• New form editor with syntax highlighting, more advanced field options & better visual feedback.
• Better support for Mailchimp address fields.
• Better support for choice fields (eg groupings, list choice & country fields).
• All fields marked as required are now validated server-side as well (instead of just Mailchimp required fields).
• All integrations have their own settings page now.
• Events Manager: checkbox is now automatically added to booking forms.
• Tons of usability & accessibility improvements.
• Tons of code improvements: improved memory usage, 100+ new unit tests & better usage of various best practices.
• The premium plugin is now an add-on of this plugin.

Additions

• New "Preview Form" option, showing unsaved form changes.
• Integrations can now be "implicit", thus no longer showing a checkbox option to visitors.
• New JavaScript API, replacing jQuery event hooks.
• Ninja Forms integration
• Introduced various new filter & action hooks, please see the new code reference for developers for more information.

Fixes

• Incorrect number of parameters for error_log statement in integrations class.

Improvements

• Usage tracking is now scheduled once a week (instead of daily).
• Preparations for the upcoming Mailchimp for WordPress version 3.0 release.
• Tested compatibility with WordPress 4.4

Fixes

• Honeypot field being autofilled in Chrome, causing a form error.

Improvements

• Updated Portugese translations.

Fixes

• Error in Russian translation, causing a broken link on the Mailchimp settings page.

Improvements

• Textual improvements to Mailchimp settings page.
• Connectivity issues with Mailchimp will now always show an error message.
• Renewing Mailchimp lists will now also update the output of the {subscriber_count} tag.

Fixes

• Fixes JS error when form contains no submit button

Improvements

• Only prefix url fields with http:// if it is filled.
• Updated Spanish & Catalan translations, thanks to Xavier Gimeno Torrent.
• Fix mc4wp_form_before_fields being applied twice.
• Position honeypot field to the right for Right-To-Left sites.
• _mc4wp_lists can now be a comma-separated string of Mailchimp list ID's to subscribe to (or an array).
• Minor other defensive coding improvements to prevent clashes with other plugins.

Additions

• Added opt-in usage tracking to help us make the plugin better. No sensitive data is tracked.

Fixes

• Use of undefined constant in previous update.

Fixes

• Honeypot causing horizontal scrollbar on RTL sites.
• List choice fields not showing when using one of the default form themes.

Improvements

• Minor styling improvements for RTL sites.
• Mailchimp list fields of type "website" will now become HTML5 url type fields.
• Auto-prefix fields of type url with http://

Fixes

• Issue with interest groupings not being fetched after updating to version 2.3.11

Fixes

• Honeypot field being filled by browser's autocomplete.
• Styling issue for submit buttons in Mobile Safari.
• Empty response from Mailchimp API

Improvements

• Do not query Mailchimp API for interest groupings if list has none.
• Integration errors are now logged to PHP's error log for easier debugging.

Additions

• You can now use shortcodes in the form content.

Fixes

• Showing "not connected" when the plugin was actually connected to Mailchimp.
• Issue with address fields when addr1 was not given.
• Comment form checkbox not outputted for some older themes.

Improvements

• Do not flush Mailchimp cache on every settings save.
• Add default CSS styles for number fields.
• Placeholders will now work in older version of IE as well.

Improvements

• Mailchimp lists cache is now automatically flushed after changing your API key setting.
• Better field population after submitting a form with errors.
• More helpful error message when no list is selected.
• Translate options when installing plugin from a language other than English.
• Add form mark-up to WPML configuration file.
• Sign-up checkbox in comment form is now shown before the "submit comment" button.
• URL-encode variables in "Redirect URL" setting.
• Better error message when connected to Mailchimp but account has no lists.

Additions

• Add mc4wp_form_action filter to set a custom action attribute on the form element.

Fixes

• Prevented JS error when outputting forms with no submit button.
• Using 0 as a Redirect URL resulted in a blank page.
• Sign-up checkbox was showing twice in the Easy Digital Downloads checkout when showing registration fields, thanks Daniel Espinoza.
• Default form was not automatically translated for languages other than English.

Improvements

• Better way to hide the honeypot field, which stops bots from subscribing to your lists.
• role="form" is no longer needed, thanks XhmikosR!
• Filter mc4wp_form_animate_scroll now disables just the scroll animation, not the scroll itself.
• Revamped UI for Mailchimp lists overview
• Updated German & Greek translations.

Additions

• Added mc4wp_form_is_submitted() and mc4wp_form_get_response_html() functions.

Improvements

• Use the same order as Mailchimp.com, which is useful when you have over 100 Mailchimp lists.
• Use /* ... */ for inline JavaScript comments to prevent errors with minified HTML - props Ed Gifford

Additions

• Filter: mc4wp_form_animate_scroll to disable animated scroll-to after submitting a form.
• Add {current_path} variable to use in form templates.
• Add default attribute to {data_name} variables, usage: {data_something default="The default value"}

Fixes

• Undefined index notice when visitor's USER_AGENT is not set.

Improvements

• Relayed the browser's Accept-Language header to Mailchimp for auto-detecting a subscriber's language.
• Better CSS for form reset
• Updated HTML5 placeholder polyfill

Fixes

• Faulty update for v3.0 appearing for people running GitHub updater plugin.

Improvements

• Updated language files.
• Now passing the form as a parameter to mc4wp_form_css_classes filter.

Fixes

• Issue with GROUPINGS not being sent to Mailchimp

Improvements

• Code preview in Field Builder is now read-only

Fixes

• Get correct IP address when using proxy like Cloudflare or Sucuri WAF.
• Use strict type check for printing inline CSS that hides honeypot field

Improvements

• Add contactemail and contactname to field name guesses when integrating with third-party form.
• Re-enable sslverify

Fixes

• Groupings not being sent to Mailchimp
• Issue when using more than one {data_xx} replacement

Improvements

• IE8 compatibility for honeypot fallback script.

Fixes

• PHP notice in includes/class-tools.php, introduced by version 2.3.

Fixes

• The email address is no longer automatically added to the Redirect URL as this is against Google Analytics policy. To add it again, use ?email={email} in your Redirect URL setting.
• Registration type integrations were not correctly picking up on first- and last names.
• JavaScript error in IE8 because of setAttribute call on honeypot field.
• API class subscribe method now always returns a boolean.

Improvements

• Add role attribute to form elements
• Major code refactoring for easier unit testing and improved code readability.
• Use Composer for autoloading all plugin classes (PHP 5.2 compatible)
• You can now use form variables in both forms, messages as checkbox label texts.

Additions

• You can now handle unsubscribe calls with our forms too.
• Added Portugese, Indonesian, German (CH) and Spanish (PR) translations.

Fixes

• Menu item for settings page not appearing on Google App Engine (#88)

Improvements

• Updated Italian, Russian & Turkish translations.

Fixes

• API key field value was not properly escaped.
• Background images were stripped from submit buttons.

Improvements

• Better sanitising of all settings
• Updated all translations

Additions

• Added mc4wp_before_checkbox and mc4wp_after_checkbox filters to easily add more fields to sign-up checkbox integrations.
• Added some helper methods related to interest groupings to MC4WP_MailChimp class.
• Allow setting custom Mailchimp lists to subscribe to using lists attribute on shortcode.

Fixes

• Honeypot field was visible for themes or templates not calling wp_head() and wp_footer()

Improvements

• Various minor code improvements
• Updated German, Spanish, Brazilian, French, Hungarian and Russian translations.

Additions

• Added mc4wp_form_success action hook to hook into successful sign-ups
• Added mc4wp_form_data filter hook to modify all form data before processing

Fixes

• CSS reset wasn't working for WooCommerce checkout sign-up checkbox.
• mc4wp-submitted class was not added in IE8
• Incorrect action attribute on form element for some server configurations

Improvements

• Anti-SPAM improvements: a better honeypot field and a timestamp field to prevent instant form submissions.
• Reset background-image on submit buttons when using CSS themes
• Smarter email detection when integrating with third-party forms
• Updated all translations

Additions

• Custom fallback for browsers not supporting input[type="date"]

Fixed

• Issue where WooCommerce checkout sign-up was not working for cheque payments.
• Translation were loaded too late to properly translate some strings, like the admin menu items.

Improvements

• The presence of required list fields in form mark-up is now checked as you type.
• Number fields will now repopulate if an error occurred.
• Updated all translations.
• Make sure there is only one plugin instance.
• Various other code improvements.

Additions

• Added support for GitHub Updater Plugin.
• You can now specify whether you want to send a welcome email (only with double opt-in disabled).

A huge thank you to Stefan Oderbolz for various fixed and improvements related to translations in this release.

Fixed

• Textual fix as entering "0" for no redirection does not work.

Improvements

• Moved third-party scripts to their own directory for easier exclusion
• All code is now adhering to the WP Code Standards
• Updated Dutch, German, Spanish, Hungarian, French, Italian and Turkish translations.

Additions

• Now showing a heads up when at limit of 100 Mailchimp lists. (#71)
• Added wpml-config.xml file for better WPML compatibility
• Added filter mc4wp_menu_items for adding & removing menu items from add-ons

Minor improvements and additions for compatibility with the Mailchimp User Sync plugin.

Fixes

• Plugin wasn't connecting to Mailchimp for users on Mailchimp server us10 (API keys ending in -us10)

Improvements

• Use JS object to transfer lists data to Field Wizard.
• Field Wizard strings are now translatable
• Add is_spam method to checkbox integration to battle spam sign-ups
• Minor code & code style improvements
• Updated Danish, German, Spanish, French, Italian and Portugese (Brazil) translations

Additions

• You can now set MC_LOCATION, MC_NOTES and MC_LANGUAGE from your form HTML
• The submit button now has a default value when generating HTML for it

Fixes

• "Select at least one list" notice appearing when unselecting any Mailchimp list in Form settings
• If an error occurs, textareas will no longer lose their value

Improvements

• Improved the way form submissions are handled
• Minor code & documentation improvements
• Updated Dutch, French, Portugese and Spanish translations

Additions

• Added sign-up checkbox integration for WooCommerce checkout.
• Added sign-up checkbox integration for Easy Digital Downloads checkout.
• The entered email will now be appended to the URL when redirecting to another page