Feed by mail update error

Hello,
inside my plugins, i see that “Feed by Mail Extension for Newsletter” requires update.

When i choose to see “Details” i get that an “unexpected error” and cannot update.

The version i use is 2.0.5.

How can i fix this?

Also, when i am in the Feed options and i choose “Send now” i get the following:
Fatal error: Call to undefined method NewsletterFeed::get_prefix() in /home/xxxx/public_html/romanian/wp-content/plugins/newsletter-feed/feed.php on line 442

I tried to re-install, but i still get the same error.

Also, any fix for this??

Thank you