Bump WordPress Tested up to version 7.0

[qasumitbagthariya]

Description of the Change

PR bumps WordPress "tested up to" version 7.0 and bump WordPress minimum supported version to 6.6.

There are few UI issue reported as part of manual testing, those issue are also addressed.

Admin Notices Refactor:

• Introduced a new Mailchimp_Admin_Notices class to handle admin notices as a singleton, queuing and rendering notices in a standardized way.
• Refactored legacy admin_notice_success and admin_notice_error functions to delegate to the new class, marking them as wrappers and preparing them for deprecation. (Haven't used new class everywhere yet to avoid major refactoring in this compact PR)

WordPress Version Updates:

• Updated the minimum required WordPress version to 6.6 in plugin headers, test workflows, and code style config files.
• Updated the "Tested up to" version in readme.txt to 7.0.

Minor UI Fix:

• Ensured checked radio buttons in the admin UI have a white background for better visibility.

Closes #202

How to test the Change

1. Run the e2e test using GitHub action to test this PR.
2. Do thorough manual visual validation, with a strong focus on the admin interface

Changelog Entry

Dev - Bump WordPress "tested up to" version 7.0.
Dev - Bump WordPress minimum supported version to 6.6.

Credits

Props @qasumitbagthariya @iamdharmesh

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[qasumitbagthariya]

QA Update ❌

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Issue 1:

When saving the settings, the settings page turns blank for a few seconds, while the “settings saved” notice appears at the top. After a few seconds, the page reloads and displays normally again.

Steps to Reproduce:

1. Navigate to the settings page
2. Make any changes
3. Click on the Save button

Expected Result:

1. The settings page should reload or update smoothly without showing a blank screen
2. The success notice should appear without any UI flicker or disruption

Screen.Recording.2026-03-27.at.1.43.24.PM.mov

cc @iamdharmesh

[vikrampm1]

@iamdharmesh this appears to be awaiting your review. It would be good to take a look and move this forward to the next step. Thanks!

[Copilot]

Pull request overview

Updates plugin compatibility metadata for upcoming WordPress 7.0 and aligns tooling/CI with the new minimum supported WordPress version. In addition, this PR introduces a small refactor for admin notice rendering and a minor admin UI styling adjustment.

Changes:

• Bump “Tested up to” to WordPress 7.0 and minimum supported WordPress version to 6.6 (readme + plugin header + PHPCS + CI matrix).
• Introduce Mailchimp_Admin_Notices for centralized admin notice rendering and convert legacy notice helpers into wrappers.
• Adjust admin radio button checked styling in admin.css.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
readme.txt	Updates “Tested up to” to 7.0.
phpcs.xml	Raises minimum_supported_wp_version to 6.6.
mailchimp.php	Raises plugin header “Requires at least” to 6.6 and loads new admin notices class.
includes/class-mailchimp-admin.php	Initializes the new admin notices system during admin bootstrap.
includes/admin/class-mailchimp-admin-notices.php	Adds a new centralized admin notice queue/renderer.
includes/admin/admin-notices.php	Converts legacy notice functions into wrappers around the new class.
assets/css/admin.css	Tweaks checked radio background styling.
.github/workflows/e2e.yml	Updates CI “WP minimum” to run against WordPress 6.6.

Comments suppressed due to low confidence (2)

includes/admin/class-mailchimp-admin-notices.php:116

• Because the allowed HTML for links permits target, it should also permit rel (and ideally ensure noopener noreferrer when target="_blank" is used). As-is, any provided rel attribute will be stripped by wp_kses, making it harder to avoid reverse-tabnabbing issues.

		$allowed_html = array(
			'a'      => array(
				'href'   => array(),
				'title'  => array(),
				'target' => array(),
			),
			'strong' => array(),

includes/admin/admin-notices.php:30

• This docblock also uses the placeholder "@SInCE x.x.x". Please update it to the actual version (or remove the placeholder) before merge/release.

 * Display error admin notice.
 * This function is now a wrapper around the Mailchimp_Admin_Notices class, will be deprecated in future versions. Use that class instead.
 *
 * @since 1.7.0
 * @since x.x.x - Moved notice rendering to class-mailchimp-admin-notices.php
 *

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[getdono]

Looks good 👍