4D 21 R3 Beta Starts Today

April 22, 2026 5 min read

Beta testing for 4D 21 R3 starts today, bringing centralized AI configuration, real time system reactions, modern UI rendering across platforms, and deeper control over how your code executes between client and server, all designed to reduce friction and keep logic closer to where it runs.

AI providers and model aliases in Settings: Define providers once and reference models with stable names across your code.
Real-time IMAP notifications: React instantly to mailbox changes instead of relying on polling.
Fluent UI and Liquid Glass rendering: Build once and get a modern interface on both Windows and macOS.
Server execution for singletons: Run session and shared logic on the server without moving your code.
Stronger editor feedback: Catch command parameter errors while writing, not after execution.

And that’s just the beginning, there’s much more to discover!

Download 4D 21 R3 now (Exclusive to 4D Partners)

AI Integration

CENTRALIZE AI PROVIDERS AND MODELS WITH REUSABLE ALIASES

Define AI providers once in Settings, including API keys and endpoints, and reuse them across your application. Reference models directly or through aliases that map to a provider and model, so calls resolve automatically without repeating configuration. You switch providers or models without rewriting code, keeping setup centralized and logic clean.

User Interface

LIQUID GLASS LOOK FOR 4D FORMS ON macOS

Forms now adopt the Liquid Glass system style automatically on macOS, with updated spacing, transparency, and visual feedback. Existing form logic and structure remain unchanged, so your interface aligns with current macOS standards without requiring a redesign.

BUILD MODERN INTERFACES WITH FLUENT UI AND LIQUID GLASS

The Object Library now supports Fluent UI on Windows alongside Liquid Glass on macOS. Existing components adapt to each platform without changing their definition, allowing you to maintain a consistent, modern interface across environments with the same forms.

PRINT MODERN FORMS WITH PAPER-OPTIMIZED RENDERING

Forms using modern UI styles are automatically adapted for print by flattening visual effects while preserving layout and values, including unsaved data. Output stays consistent across platforms without requiring additional print logic.

NETWORK

LEGACY NETWORK REMOVED

The Legacy network layer is removed from new projects, with QUIC and ServerNet as the default. Existing applications continue to run on a supported layer at runtime, allowing you to move forward without breaking compatibility.

RECEIVE REAL-TIME EMAIL EVENTS WITH IMAP IDLE

IMAPTransporter now supports the IDLE protocol, allowing your application to react to mailbox events such as message creation or deletion through callbacks. This replaces periodic polling with a live connection, reducing unnecessary requests and keeping your app in sync with real time changes.

4D Write Pro

STRUCTURE DOCUMENTS WITH HIERARCHICAL NUMBERED LISTS

Numbered lists now support multiple levels through structured paragraph styles, automatically generating formats like 1, 1.1, and 1.1.1. Numbering updates as content changes, so long or complex documents stay consistent without manual adjustments.

4D language

ACCESS USER SESSIONS DIRECTLY FROM THE 4D CLIENT

The Session command now returns the remote session object on the client, allowing direct access to session data and functions without moving logic to the server. Code stays where it is used, making client server flows easier to manage.

EXECUTE SHARED AND SESSION SINGLETON FUNCTIONS ON THE SERVER

Shared and session singleton functions can now run on the server using the server keyword, even when called from a 4D Client. This keeps logic inside the class while controlling where it executes, without restructuring your application.

TURN DYNAMIC TEXT INTO REAL EXECUTABLE METHODS

The 4D.Method class allows code stored as text to be validated and executed as a native method, with structured parameters and detailed syntax checking. Dynamic behavior becomes safer and easier to control at runtime.

VALIDATE JSON WITH MODERN SCHEMA STANDARDS

JSON Validate now supports the latest schema standard, allowing advanced rules such as conditional logic and extended formats to be defined directly in the schema. Validation logic can be shared across systems, reducing duplication and keeping data consistent.

VALIDATE DATES CONSISTENTLY IN JSON SCHEMAS

Dates are now validated consistently whether stored as strings or native values, following the schema definition without requiring conversion logic. This avoids mismatches when data flows between APIs and internal processing.

CATCH COMMAND PARAMETER ERRORS EARLIER IN THE EDITOR

Command parameters are now validated directly in the editor using documented types and syntax rules. Invalid arguments are detected while writing code, helping you fix issues earlier and avoid runtime errors.

4D Component

MANAGE GITLAB COMPONENT DEPENDENCIES FROM THE PROJECT INTERFACE

Project Dependencies now supports GitLab repositories, allowing components to be added, versioned, and managed using the same workflow as other sources. Dependency management stays consistent across your project.

Visual Studio code extension

EDIT ROLES, PRIVILEGES, AND HTTP HANDLERS VISUALLY IN VS CODE

Roles, privileges, and HTTP handlers now open in visual editors in VS Code, where fields are organized and validated automatically. You can update configurations without navigating raw JSON, reducing errors and speeding up changes.

DEPENDENCIES NOW FULLY RECOGNIZED IN VS CODE

The 4D-Analyzer extension now loads project dependencies like the 4D IDE, ensuring syntax checking and code completion use the same context. Feedback stays consistent across environments.

Security

USE MACOS KEYCHAIN CERTIFICATES DIRECTLY IN HTTPS REQUESTS

HTTPS requests and HTTP agents can now use certificates stored in the macOS Keychain by referencing them by name. Certificates stay managed by the system, removing the need to store or distribute them within the application.

Need more technical details? The 4D 21 R3 Beta documentation is available on the 4D Doc Center.

Your feedback is greatly appreciated and will help us improve our product quality and better serve your needs. We’d love to hear your thoughts about any of the features above. Contribute to our beta forum (accessible for all 4D Partners). And don’t hesitate to tell us about your needs; we take votes very seriously!

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