A customer asked me about the requirements for licensing their use of MS SQL Server as they know that Sage CRM runs on MS SQL Server. MS SQL Server and the Windows server both need to be correctly licensed. This article is my understanding of the issues around licensing. Partners need to advise customers that licensing is required and is their responsibility. I recommend you refer to the guides provided by Microsoft. I have provided links to the key guides below. I have assumed that the customer is working with an on-premise instance of Sage CRM integrated with a Sage accounting system such as Sage 300 or Sage 200. The two share the same MS SQL Server.Microsoft requires you to either license for a core, a physical server (i.e. all the cores in the server) or on a Server plus Client Access License (CAL) basis. Microsoft provides an overview of client access licensing here. https://www.microsoft.com/en-us/licensing/product-licensing/client-access-licenseThe access to the database for Sage CRM users is through a shared connection to the database. This type of connection is called multiplexing. Multiplexing is when the software design reduces the number of devices or users that directly access or use SQL Server. Microsoft SQL Server requires a CAL for each unique client regardless of how many will be connecting at any single point in time.You can read about Microsoft's licensing requirements within multiplexing systems here. https://download.microsoft.com/download/8/7/3/8733d036-92b0-4cb8-8912-3b6ab966b8b2/multiplexing.pdfIn a Sage CRM environment, this is going to be the number of users who at any time *could* access the system, not the devices by which they access the system. So you may have 20 named or 20 concurrent - this means that you could have 20 users interacting with the database. They could be using Outlook integration features or their mobile device but there are still only 20 of them.Example ScenarioBut let us consider some example scenarios.Imagine we have a new customer who has purchased a Sage accounting system integrated with Sage CRM. The licensing requirements are determined by your user profiles. That is how many users could access the system at any one time. I have assumed that there is overlap with the accounting system users and the Sage CRM usersScenario AThere are five Sage accounting system users and 15 CRM "named" users. Three of the Sage CRM users are also Sage accounting users. They will need five CALS (for the Sage accounting system) and an additional 12 licenses CALS for CRM. The CALS are counted on the maximum number of users who may access the system.Scenario BThere are five Sage accounting system users and 15 CRM users. The Sage CRM system is using a concurrent license model and has a license count of six. Three of the Sage CRM users are also 200 users. In this case, they will need five CALS for 200 the Sage accounting system and an additional six CALS for the Sage CRM users. The CALS are counted on the maximum number of users who may access the system.Note 1: Concurrent licensing for Sage CRM is not available in all markets. Please refer to your local Sage team for advice.Note 2: There are different considerations if the instance of MS SQL Server runs in a hosted environment and virtualisation may also need to be considered. If a customer implements Sage CRM within a hosted environment and has a requirement to host Microsoft SQL Server then the customer will need to purchase Subscriber Access Licenses (SAL) under the Microsoft Services Provider License Agreement.Licensing Microsoft server products for use in virtual environments: https://download.microsoft.com/download/3/d/4/3d42bdc2-6725-4b29-b75a-a5b04179958b/microsoftservervirtualization_licensemobility_vlbrief.pdfWhat would change the nature of the requirements is if you are using Self Service and integrating Sage CRM into a corporate web site. Then you are likely to use licensing based on the server or core. This is because every person who accesses data from the database needs to be licensed. Therefore, it may be cheaper to do the core licensing as it covers every eventuality.