The plugin currently states a WordPress minimum of 2.8:

and currently shows as tested-up-to WordPress 4.5:

As part of this issue, we'll want to look to:

• test and ensure/add compatibility for WordPress 6.5
• bump WP minimum to either 6.3 or a lower version per need within codebase or Mailchimp constraints
• bump WP tested-up-to 6.5
• add WP version checker action: https://github.com/10up/insert-special-characters/blob/develop/.github/workflows/wordpress-version-checker.yml
• add ZIP build action: https://github.com/10up/insert-special-characters/blob/develop/.github/workflows/build-release-zip.yml
• add e2e test framework (Playwright or Cypress): https://github.com/10up/insert-special-characters/blob/develop/.github/workflows/cypress.yml