Reference:
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/dev-itpro/data-entities/integration-overview

Explanation
Base licenses and cost savings opportunities for "attach" licenses
Microsoft provides a cost-effective way for a single Dynamics 365 user to obtain full user licensing for multiple products. Licenses for products that provide core business functionality qualify as base licenses. (See the table below.) Each has one or more additional applications that are frequently used by people in the same roles and that qualify as attach licenses for that user. (These are sometimes referred to as subsequent qualifying applications.) To take advantage of the special attach license pricing:
1. Buy the first base user license at standard pricing.
2. Review which attach licenses are available for that base. (See the qualifying products for each base license below.)
3. Buy attach licenses for the same user at an attach license price. You may buy as many attach licenses as are available for that base license.
Reference: https://go.microsoft.com/fwlink/p/?LinkId=866544 (Dynamics 365 Licensing Guide)

Explanation
Note:
* The CTO has learned that there are updates to globalization features in Dynamics 365 Finance. The IT staff has been tasked with ensuring that they are the first group to receive these updates.
* The IT department has decided not to code for globalization issues because they are in an upcoming service update. They are closing in on go-live and need to make sure that the updates are applied in time.
Service updates are continuous, touchless updates that provide new features and functionality. You are in control and manage how your organization receives these updates. For example, you can sign up for the First Release program so that your organization receives updates first. You can apply the updates to any of your environments manually (self-update) or remain on the default release schedule and receive the auto-updates when you schedule them using LCS.
Reference:
https://docs.microsoft.com/en-us/dynamics365/fin-ops-core/fin-ops/get-started/public-preview-releases