awesomemotive/WP-Mail-SMTP v2.1.1 on GitHub

Changed: Remove current automatic default reply-to address and add WP filter wp_mail_smtp_processor_set_default_reply_to for setting default reply-to addresses.
Changed: Improve description for several options with links to an article about how to properly use constants.
Fixed: PHP parse error connected to Monolog library on PHP versions < 7.x.

Added: Async/scheduled tasks management support.
Added: New warning notification for selecting the "Default (none)" mailer and saving the plugin settings.
Changed: Set the original From Email as Reply-To address if it was overwritten by the Force From Email option.
Changed: The Force From Email option is now enabled by default, for new plugin installs.
Changed: Reply-To header is now set when not provided, equals to From Name/Email.
Fixed: Display a non-empty PHPMailer error when some non-SMTP mailers generate errors.
Fixed: Display a more accurate message, when the "channel - not found" error is triggered by SMTP.com API.
Fixed: Save and display debug errors for the "Other SMTP" mailer.
Fixed: Improve the debug details for the "Invalid address (setFrom)" error in the Email Test tab.
Fixed: Improve the debug details for SMTP CA verification fail, Gmail Guzzle requirements, and Gmail invalid grant errors.
Fixed: Improve the uninstall cleanup procedure.