My security scanner did throw a vulnerability for your plugin v2.0.3. But although there seems to be an updated version, automatic updates fail.
The current download file is displayed as version 2.0.3. The changelog and the download link are marked as version 2.0.4. The downloaded file
subscribe-to-comments-reloaded.php still contains v2.0.3 as version number. This will result in no automatic updates for already installed plugins. You have to increase the verion number in the file to trigger automatic updates.