What are the Differences Between Oracle Database 23ai and 26ai? Explaining How Patching Transforms it into “26ai”

Among engineers and IT architects following the latest information on Oracle Database, the two version notations—”23ai” and “26ai”—are currently causing the most confusion.

“Where did 23ai go?” “Is 26ai a completely different product?” “Do we have to verify everything from scratch again?”

To give you the conclusion first: these are not different things. “Oracle Database 23ai” has been officially renamed (rebranded) to “Oracle AI Database 26ai”.

However, this involves more technical implications than a mere name change. This article details the mechanism of this slightly unique versioning, the strategy behind Oracle Corporation, and practical points that engineers need to know.

Conclusion: 23ai Becomes “26ai” by Applying a Patch
Why Does the Name Change with a “Patch”? Technical Background
1. Version Numbering Rules and Branding
2. Concrete Image of Changes: What is Happening Inside?
Release Status of 23ai and Roadmap to Join 26ai
Operational Caution Points: “Unexpected Changes” due to Patching
Summary: How Engineers Should Move

Conclusion: 23ai Becomes “26ai” by Applying a Patch

The relationship between Oracle Database 23ai and 26ai can be summarized in one sentence: “The base is the same product, and by applying a specific update (patch), the product name itself evolves into ’26ai’.” This change overturns the conventional wisdom of Oracle Database.

Oracle Database 23ai: The base release (code line 23). After October 2025, this name will be treated as an “old name” or a “transitional name”.
Oracle AI Database 26ai: The form of 23ai after applying the Release Update (RU 23.26) of October 2025 or later. This will serve as the official “Long Term Release” with a support period of 5 to 8 years or more.

In other words, high-cost “major version upgrade” tasks—such as replacing the OS or migrating data (Export/Import)—are unnecessary. Simply applying a patch to your existing 23ai environment will turn your database into “26ai”.

Why Does the Name Change with a “Patch”? Technical Background

Version Numbering Rules and Branding

Until Oracle Database 23ai, applying a patch (Release Update: RU) did not change the name “23ai”. The internal version would strictly rise from 23.4 to 23.5, but the product banner never changed.

However, with the announcement in October 2025, the product branding was revamped to “Oracle AI Database”. Along with this, the numbering rules for Release Updates (RU) were changed to include the “last two digits of the calendar year” in the version. This aims to prevent the product name from becoming obsolete amidst the rapid evolution of AI technology.

Old Rule: 23.4, 23.5… (Treated as minor version upgrades of 23c/23ai)
New Rule: 23.26.0 (The October 2025 RU looking ahead to 2026)

Concrete Image of Changes: What is Happening Inside?

When confirmed on an actual machine, the “banner information (product name)” changes clearly before and after applying the patch. However, the important point here is that “the base version remains 23.”

Before Patch Application (23ai)

SQL> SELECT banner FROM v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 23ai Enterprise Edition Release 23.0.0.0.0 - Production

↓ After Patch (RU 23.26 or later) Application

SQL> SELECT banner FROM v$version;

BANNER
--------------------------------------------------------------------------------
Oracle AI Database 26ai Enterprise Edition Release 26.0.0.0.0 - Production

Although it looks like “26”, the basic behavior of the optimizer and the core structure of the data dictionary inherit the 23 series. Therefore, compared to the upgrade from 19c to 23ai, the change from 23ai to 26ai is positioned as “a very low-risk update as part of operations.”

Release Status of 23ai and Roadmap to Join 26ai

Due to changes in the release roadmap, the situation differs for each platform. This represents a major policy shift, especially for users waiting for the on-premises version.

1. Cloud & Exadata Versions (Released) Become 26ai via Patch

For Oracle Cloud (OCI) and Exadata, Oracle Database 23ai has already been provided (Base Database Service, Exadata Database Service, etc.). Users currently utilizing these existing environments do not need to panic.

Conclusion: You can continue using it as is without issues.
Action: By applying future patches (RUs), it will automatically update to the 26ai specification.

Simply pressing the “Apply Patch” button from the OCI management console changes the database from “23ai” to “26ai”. Rebuilding or data migration is completely unnecessary.

2. General On-premises Version (Linux/Windows) Skips “23ai”

On the other hand, the probability is high that the “23ai On-premises Version” for installation on general servers (Linux/Windows, etc.) will end without being released (will be skipped).

23ai: The general on-premises version was “Coming Soon” for a long time, but there is no sign of release, and it will effectively become a “missing number”.
26ai: The official release of the on-premises version (Enterprise Edition / Standard Edition 2) is scheduled for January 2026.

As a result, the target for the “next on-premises DB” considered by many companies will be unified not to 23ai, but to “26ai”. Companies whose strategy was to “wait on 19c until 23ai comes out” need to correct their target to “26ai” and push their plans back by a few months.

[reference]
Oracle AI Database 26ai coming soon for Linux x86-64 on-premises platforms | database

3. [Good News] Developer “26ai Free” is Released!

While the on-premises version for enterprise is on hold until 2026, the free version for developers, “Oracle AI Database 26ai Free”, has already been released and is available for download.

How to Get: Available via Oracle Container Registry (Docker) or RPM packages from the official site.
Usage: For verification, learning, and small-scale app development, you can build a “26ai” environment on your local PC (Docker, etc.) right now to check new features and behavior.

Engineers who “cannot wait until the product version is out” or “want to try executing 26ai commands for now” should definitively start learning with this Free version first.

[reference]
AI Database 26ai Free | Oracle

Operational Caution Points: “Unexpected Changes” due to Patching

While “becoming a new version just by applying a patch” is convenient, it can be a pitfall for operation managers. We dig deeper into points to be careful about in practice.

1. Application Version Check Processing

In many legacy applications or custom-developed management tools, there are cases where the connection destination database version is determined by string matching.

Example of Risky Code (Pseudo-code)

String dbVersion = getDBVersion(); // Retrieved from v$version
if (dbVersion.contains("23ai")) {
    // Execute processing for 23ai
} else {
    throw new Exception("Unsupported version");
}

If such logic is embedded, there is a risk that the application will stop the moment the patch (RU) is applied and the banner changes to “26ai”. It is necessary to check the application code in advance and correct the version judgment logic to a form like “23 or higher” or including “26ai”.

2. COMPATIBLE Parameter and the “Point of No Return”

Patch application itself is an update of binaries, but to fully utilize new features (especially persistence features related to AI), it may be required to raise the initialization parameter COMPATIBLE to 26.0.0, etc.

Caution: Once the COMPATIBLE parameter is raised, it cannot be lowered (downgraded).
Measure: A cautious procedure is required, such as operating with COMPATIBLE unchanged immediately after patching, raising it after confirming stable operation, or changing it only after securely taking a backup.

3. Unlocking AI Features and Resource Consumption

By converting to 26ai, features such as AI Vector Search are enhanced and enabled as the official version. While these are available at no additional cost, background processes may increase.

Resource Management: Due to the maintenance of vector indexes and the loading of AI models, the usage baseline of memory (SGA/PGA) and CPU may change.
Sizing: For systems operating with barely enough resources, performance verification after patch application is mandatory.

Summary: How Engineers Should Move

Not a Different Product: 23ai and 26ai are products on the same code line, and the knowledge learned will not be wasted.
Evolution via Patch: By applying a patch (RU 23.26 or later) to 23ai, it becomes “Oracle AI Database 26ai”. Since this can be an irreversible change, plan the application carefully.
Existing 23ai also to 26ai: Released Cloud/Exadata versions will also support 26ai via patches.
On-prem Waits for 26ai: The Enterprise version is scheduled for January 2026, but the “26ai Free” version has already been released. Let’s start getting hands-on with the Free version and prepare for the next production environment.

There is no need to be defensive about the new name “26ai”. The reality is “the completed form of 23c/23ai with enhanced AI functions and a refreshed name.” First, solidifying the basics with 19c, and then learning the architecture common to 23ai/26ai (CDB/PDB, etc.) is the most efficient and certain path to improving your skills.

Note: This article is based on the Oracle Database release strategy and patch application specifications as of October 2025. Please check Oracle Support (My Oracle Support) for the latest patch information and release notes.