Yesterday we released v4.0 of the Sailthru plugin for WordPress. This release supports an update to support the new version of the PHPMailer library included in WordPress 5.5. In addition, we’ve released a bug fix related to our signup widget when configured for double opt-in.To update for full WordPress 5.5 support, update your plugin to version 4.0. If not yet on WordPress 5.5, we also have patch-released 3.6.1 to get the latest bug fix.