Deprecated: Using ${var} in strings is deprecated, use {$var} instead

When I have WP fail2ban Blocklist activated, I get the following warnings in DEBUG:

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 68

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 68

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 70

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 72

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 73

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 73

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 73

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 77

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /var/www/vhosts/cfloinc.com/staged.cfloinc.com/wp-content/plugins/wpf2b-addon-blocklist/admin/widgets.php on line 78

seems like an easy fix, if you update the syntax. Please issue a fix and let me know so I can re-enable this plugin without errors