On August 22, 2025, Microsoft announced the first Release Candidate (RC0) of SQL Server 2025. This version marks an important step toward general availability, featuring enhancements in performance, stability, and new functionality based on feedback from the preview phase.
SQL Server 2025 places a strong focus on AI integration, improved support for data analytics, cloud-hybrid scenarios, and developer tools. Below, we discuss what is truly new, followed by how core-based licensing (and its alternatives) works and whether anything has changed compared to previous versions such as SQL Server 2022.
What’s New or Improved in SQL Server 2025
Vector Data Type and Functions
SQL Server 2025 introduces a new data type that allows you to store vector values (for example, embedding vectors from AI applications) directly in the database. This enables you to perform vector-based calculations and operations natively without relying on external tools.
Vector Index and Similarity Search
Support has been added for vector indexes, allowing you to quickly search for similar vectors (approximate similarity search). This is especially useful for AI, machine learning, and search solutions where semantic similarity matters.
Integration of ONNX Models
With the new CREATE EXTERNAL MODEL statement, you can host ONNX models locally within SQL Server. This allows AI inference to be performed directly inside the database without the need for separate ML services. This feature is available via the preview features option.
Change Event Streaming
SQL Server 2025 can stream table changes (such as inserts, updates, and deletes) as events in near real time. These events can then be forwarded to Azure or other systems, making integrations faster and easier.
New T-SQL Functions
The T-SQL language has been expanded with powerful new functions, such as:
REGEXP_MATCHESandREGEXP_SPLIT_TO_TABLEfor regex matching and splitting.New JSON aggregation functions like
JSON_OBJECTAGGandJSON_ARRAYAGG, which significantly simplify working with JSON data.
Copilot Integration in SSMS
Within SQL Server Management Studio, you can now use Copilot. This allows you to ask questions in natural language and gain insights faster without writing complex queries.
Hybrid and Cloud Integration
Integration with Azure Arc has been improved, providing better support for hybrid scenarios. This makes it easier to connect on-premises databases to the cloud and operate flexibly across multi-cloud environments.
Performance Enhancements
Improved automatic plan correction, with Trace Flag 12618 now enabled by default.
Optimized page dispatching in Always On environments, resulting in faster and more stable high availability and failover performance.
Preview Features Configuration
A new database setting is available that allows you to optionally enable experimental features. This lets you test new capabilities without risking your production environment.
New Standard Developer Edition
Microsoft is releasing a free Developer Edition that includes all features of the Standard Edition. This makes it easier for developers to build and test their applications in an environment similar to production.
Deprecated or Phased-Out Features
Some features are no longer supported or have been marked for removal. Examples include:
Hot add CPU is being deprecated.
Lightweight pooling is being phased out.
At the time of writing, SQL Server 2025 is still in preview and primarily intended for testing environments. If you need a SQL Server license right now, you can purchase SQL Server 2022, a long-term supported and widely adopted version for production use.
At Softtrader, you can purchase a Microsoft SQL Server 2022 Pre-Owned license, allowing your company to save significantly compared to Microsoft’s new license pricing.
Licensing SQL Server 2025: How Does Core-Based Licensing Work?
Licensing is one of the most complex aspects of SQL Server. With the release of SQL Server 2025, the fundamentals remain largely the same. The core-based licensing model continues to operate much like in previous versions. However, there are key details worth understanding, such as alternative models and hybrid scenarios.
Below is a step-by-step explanation of how core-based licensing works, what alternatives exist, and what is new in SQL Server 2025.
The Per Core Model
The core-based licensing model operates on a few key principles:
Licenses are purchased based on the number of physical (or virtual) cores on which SQL Server runs.
Licenses are always sold in two-core packs (2-packs).
For physical servers, all physical cores in use must be licensed. Hyper-threading does not count; calculations are based solely on physical cores.
A minimum of four cores per processor applies, regardless of the actual number of cores. This minimum remains in effect for SQL Server 2025.
For virtual machines (VMs), you must assign licenses based on the number of allocated virtual cores (v-cores). Typically, a minimum of four v-cores per VM also applies.
In the Enterprise Edition, you can use unlimited virtualization under certain conditions. If all physical cores on the host are licensed, you can run an unlimited number of SQL Server instances on that host, including across multiple VMs.
Alternative: Server + CAL Model
In addition to the Per Core model, there is also the Server + CAL (Client Access License) model. Here is how it works:
You purchase a Microsoft server license for each SQL Server installation.
For each user or device that accesses the server, you must also purchase a CAL.
Although this model remains available in 2025, Microsoft is gradually limiting its use in new licensing agreements, especially for larger environments. As a result, it is primarily still attractive for small organizations with a limited and stable number of users.
Example Calculations
Physical server: a machine with 2 CPUs, each with 8 cores (total 16 cores).
You must license all 16 cores.
Core licenses are sold in 2-packs. You need 8 packs in total.
Virtual machine: a VM with 6 assigned v-cores.
A minimum of 4 cores applies, so you must license 6 cores.
That means 3 packs of 2 core licenses.
Enterprise unlimited virtualization: a host server with 20 physical cores.
If you license all 20 cores with the Enterprise Edition, you may run an unlimited number of SQL Server VMs on that host at no additional cost per VM.
Hybrid and Cloud Scenarios in 2025
Microsoft is placing more emphasis on hybrid environments and Azure Arc integration in 2025.
This means organizations can run SQL Server in a combination of on-premises and cloud environments. The core licenses remain the foundation:
When SQL Server runs on-premises, the standard core rule applies (physical or virtual cores count).
In the cloud (Azure or other providers), licensing is based on assigned v-cores.
With Software Assurance, there is flexibility to use licenses both on-premises and in the cloud (mobility rights).
Has Licensing Changed in SQL Server 2025?
Based on the available documentation and announcements, the core licensing principles in SQL Server 2025 have not fundamentally changed. The well-known rules such as “license all cores,” the minimum core requirement, 2-core packs, and virtual core counting remain applicable. However, there are a few important notes.
The documentation states that the “Server + CAL” (Client Access License) option still exists, but in new licensing agreements it is often restricted or no longer offered. Additionally, some sources suggest that Microsoft may place more emphasis on core-based licensing in 2025, which could further reduce the use of Server + CAL in larger environments.
There is also increased focus on hybrid and cloud scenarios, indicating that licensing methods for combined on-premises and cloud environments are becoming more significant. According to the preview documentation, the basic rules for cores remain unchanged.
The conclusion is that core licensing in SQL Server 2025 largely works the same as in previous versions: you count the cores and purchase core licenses. However, there is clearly more emphasis on modern scenarios, cloud usage, and developer-friendly licenses.
Practical Considerations & Tips for SQL Server 2025
Choose the core model for unpredictable use: If you have many users or external access, the per-core model is usually simpler than Server + CAL.
Use Enterprise for virtualization: If you run many VMs, the Enterprise Edition can be more cost-effective due to its unlimited virtualization capabilities.
Use the new Standard Developer Edition: For development and testing, the new free Standard Developer Edition is convenient. You do not need to purchase production licenses just to test on an identical version.
Be cautious with “preview features”: Features activated via PREVIEW_FEATURES may fall outside standard support or licensing behavior. Use them primarily for testing purposes.
Plan for cloud and hybrid scenarios: Since SQL Server 2025 offers strong integration with Azure Arc and hybrid architectures, it is important to consider potential cloud migrations or environment splits in your license planning.
Check license bundles and price changes: Some analyses suggest that SQL Server 2025 may introduce pricing pressure due to AI-related functionality, which could increase licensing costs for organizations.
Recommendation for SQL Server 2025
SQL Server 2025 maintains the familiar core-based licensing model but builds upon it with AI and vector support, hybrid integration features, and cloud connectivity. It also includes developer-friendly editions such as the new Standard Developer Edition.
If you plan to upgrade or start fresh with SQL Server 2025, pay close attention to your licensing choice (core vs CAL), the role of virtualization, and how you plan to use the new AI capabilities without incurring unnecessary licensing costs.
Do you have questions about SQL Server licensing? Contact us, and we will advise you on the best approach for your specific situation. If you are interested in older versions of SQL Server, request a quote in advance.
FAQ
When will SQL Server 2025 be available?
Microsoft released the first Release Candidate (RC0) on August 22, 2025. General Availability (GA) is expected later in 2025, depending on feedback from the testing phase.
What is the main difference between SQL Server 2025 and 2022?
SQL Server 2025 focuses strongly on AI integration, vector data, cloud and hybrid support, and performance improvements. Functionally, it remains familiar but introduces modern extensions for data analysis and machine learning.
Is SQL Server 2025 ready for production environments?
Not yet. The current version (RC0) is a preview release intended for testing and development environments. SQL Server 2022 is still recommended for production use.
Has the licensing model changed in SQL Server 2025?
No, the core-based model remains largely the same as in SQL Server 2022.
The main principles remain:
Licenses per physical or virtual core.
Sold in 2-core packs.
Minimum of 4 cores per processor.
What is Azure Arc integration?
SQL Server 2025 is better integrated with Azure Arc, allowing you to manage on-premises databases as if they were cloud resources. This provides greater flexibility, centralized management, and support for hybrid scenarios.
What is the new Standard Developer Edition?
Microsoft is introducing a free Developer Edition that includes all features of the Standard Edition. This version is ideal for developers and testers who want to build and test their applications in an environment identical to production, without additional licensing costs.
