7.6.4 is the Provisioning Services version for Cumulative Update 3 of the Long Term Service Release (LTSR) program. Provisioning Services 7.6.4 can also be used by non-LTSR customers to upgrade 7.6 base environments.
Your benefits of upgrading to 7.6.4 include:
Permissions to download Provisioning Services 7.6.4 are based on valid Citrix Software Maintenance (or the functionally equivalent combination of Legacy Support and Subscription Advantage). For more information on eligibility and access, refer to XenApp and XenDesktop Servicing Options. After you choose your product-edition combination from the list below, if you need help related to permissions, contact Customer Service.