Class ‘WPCF7_Service’ not found

I am migrating a site from one host to LiquidWeb. Everything moved over fine but WordPress was very out of date (3.5.1) as were many plugins so I updated them. Everything updated fine except Contact Form 7 which gives this error as soon as I “Activate” it (ver. 4.8): Fatal error: Class ‘WPCF7_Service’ not found in /home/account_name/public_html/wp-content/plugins/contact-form-7/modules/recaptcha.php on line 3

I have Deactivated all other plugins and I still get this error. I can re-install Contact Form 7 v 3.4.2 and that works fine, but as soon as I update it I get the error message.

I did review the page https://contactform7.com/recaptcha/, but I cannot follow the directions there as I cannot access the plugin at all (or any plugin) because of the error message that is thrown.

Server environment: Linux, Apache 2.4.23, PHP 5.6.27, MySQL 5.6.35.

Any ideas on how to fix this?