Upgrade to 6.1.11 fatal error

I got a single site installation at the root directory of my domain and after trying to upgrade from 6.1.10 to 6.1.11 I got the following error:
mod_fcgid: stderr: PHP Fatal error: Class 'wfWAFConfig' not found in /var/www/vhosts/mydomain.gr/httpdocs/wp-content/plugins/wordfence/lib/wordfenceClass.php on line 725.

my htaccess file:

php_value upload_max_filesize 8M
php_value post_max_size 8M

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

# Wordfence WAF
<Files ".user.ini">
<IfModule mod_authz_core.c>
	Require all denied
</IfModule>
<IfModule !mod_authz_core.c>
	Order deny,allow
	Deny from all
</IfModule>
</Files>

# END Wordfence WAF

my user.ini file:

; Wordfence WAF
auto_prepend_file = '/var/www/vhosts/mydomain.gr/httpdocs/wordfence-waf.php'
; END Wordfence WAF

https://wordpress.org/plugins/wordfence/