PHP errors and missing compatibility info for newer WordPress versions

I wonder if this plugin is still maintained. It did not get any update for the last 3 major WordPress versions and with newer PHP version it also shows errors:

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in?…/wp-content/plugins/letter-avatars/lib/frontend/Scripts.php?on line?57

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in?…/wp-content/plugins/letter-avatars/lib/frontend/Scripts.php?on line?84

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in?…/wp-content/plugins/letter-avatars/lib/frontend/Scripts.php?on line?84

If you need a new maintainer, let me know. I use the plugin myself, maintain a number of other plugins for WordPress already and can fix these errors.