BookingCenter supports both GA4 and GA4. 

Note: You must ensure your Google Analytics Account is setup correctly. 

Setup your Google Analytics account. In order to get support for setting up Google Analytics and Campaign Conversions, customers need to work with their webmaster - it's not a service BookingCenter provides. There are literally THOUSANDS of webmasters skilled in setting up Google Analytics campaigns who can assist you.

Once you have setup your Google Analytics account, there is code your webmaster will present to you for entry into the Parameters | Marketing section of BookingCenter program.

Once you see the 'Web Tracking Code' and 'Web Tracking Last Page Code' at 

MyPMS Area: https://mypms.bookingcenter.com/site_enquiry_settings.phtml 
Members Area: https://members.bookingcenter.com/site_enquiry_settings.phtml

Have your webmaster perform some test bookings to validate their Google Analytics setup is working properly.

BookingCenter requires that an MSO 'Premium Marketing contract' is in place in order for this to work. Go to: http://www.BookingCenter.com/contact.html to request the service or call us at +1-707-874-3922 ext 201.

KEY NOTES:

Introducing the next generation of Analytics, Google Analytics 4 (GA4)

https://support.google.com/analytics/answer/10089681