WP Mailster v1.5.5 fixes a security issue.
WP Mailster v1.5.3 introduces compatibility with WordPress MU (multi-user version) and brings many improvements and fixes.
The WP Mailster v1.5.0 introduces compatibility with more PHP versions and brings improvements to the subscribe/unsubscribe forms.
Due to an unexpected issue with the profile shortcode we had to publish some intermediate versions.
The WP Mailster v1.4.11 release introduces import and export functionality for user/email data.