> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ditto.live/llms.txt
> Use this file to discover all available pages before exploring further.

# Flutter Release Notes

<Update label="5.0.0" description="Release Date: May 5, 2026">
  # 5.0 - Built for Speed and Developer Experience

  Ditto 5.0 brings significant performance improvements and a developer experience redesigned for usability. Your applications run faster with optimized queries and sync, while modern APIs and simplified patterns eliminate complexity at every turn.

  <Card title="Faster local queries" icon="bolt" horizontal>
    Automatic optimizations make your apps more responsive with zero code changes
  </Card>

  <Card title="No more schemas" icon="rocket" horizontal>
    Start building immediately without upfront type definitions
  </Card>

  <Card title="Simpler initialization" icon="sparkles" horizontal>
    Clear, modern patterns replace confusing legacy APIs
  </Card>

  <Card title="One query language" icon="code" horizontal>
    DQL handles all data operations consistently across platforms
  </Card>

  <Card title="Built-in observability" icon="chart-line" horizontal>
    Query system metrics and configuration directly with DQL
  </Card>

  <Card title="25% smaller footprint" icon="compress" horizontal>
    Faster builds, lower memory usage, cleaner codebase
  </Card>

  <Card title="Plus much more" icon="plus" horizontal>
    Advanced query features, networking improvements, and enhanced reliability
  </Card>

  ***

  ## Our Most Rigorously Tested Release

  Ditto 5.0 has undergone extensive validation in our internal mesh lab, ensuring reliability across real-world scenarios before reaching production.

  **Testing scope:**

  * **Multi-device mesh scenarios** - Validated with up to 40 concurrent devices across iOS, Android, and budget hardware
  * **Cross-platform compatibility** - Tested heterogeneous meshes mixing iOS, Android, and version combinations
  * **Extended reliability testing** - 24-hour continuous operation tests validating memory stability and connection resilience
  * **Real-world datasets** - From small 1MB datasets to large 50MB+ product catalogs
  * **Network conditions** - LAN, BLE, WiFi Aware, AWDL, and mixed transport scenarios
  * **Lifecycle edge cases** - Background/foreground transitions, network partitions, and recovery scenarios

  Every test validates performance, memory management, data integrity, and sync convergence across the scenarios that matter most to production deployments.

  ***

  ## In This Release

  This is a major version with breaking changes, but maintains backwards compatibility with v4 deployments (4.11+). Migrate at your own pace, and upgrade to v4.14 first for the smoothest transition.

  **DQL for All Data Operations:**

  * [DQL for All Data Operations](#dql-for-all-data-operations)

  **Core Capabilities:**

  * [Simplified Initialization & Configuration](#simplified-initialization-%26-configuration)
  * [Schema-Free Data Modeling](#schema-free-data-modeling)
  * [New DQL Query Features](#new-dql-query-features)

  **Performance & Platform:**

  * [DQL Query Performance Improvements](#dql-query-performance-improvements)
  * [Data Sync Performance Improvements](#data-sync-performance-improvements)
  * [Local System Observability](#local-system-observability)
  * [Additional Improvements](#additional-improvements)

  **Upgrading to v5:**

  * [Migration Guidance](#migration-guidance)
  * [Terminology Updates](#terminology-updates)
  * [Breaking Changes](#breaking-changes)

  **Flutter Specific Changes**

  * [Flutter Specific Changes](#flutter-specific-changes)

  **Full Changelog**

  * [Full Changelog](#full-changelog)

  ***

  # DQL for All Data Operations

  ## DQL for All Data Operations

  Ditto 5.0 completes the transition to DQL (Ditto Query Language) as the single API for all data operations. The legacy query builder has been removed.

  ### What Changed

  * **Legacy query builder removed**: All `store.collection()` methods and fluent query APIs are no longer available
  * **Full feature parity**: Every legacy operation has a DQL equivalent
  * **Single query language**: DQL handles reads, writes, subscriptions, and observers
  * **Works everywhere**: Same syntax across mobile, server, and web
  * **SQL-familiar**: Standard SQL patterns for immediate productivity

  ### Why One Query Language

  A unified query language means one implementation to maintain, faster feature delivery, and consistent behavior across all platforms. New capabilities and optimizations benefit every SDK simultaneously.

  ### Migration Path

  All legacy query operations have direct DQL equivalents:

  **Update Operations:**

  <CodeGroup>
    ```dart Flutter - DQL (v5) theme={null}
    await store.execute(
        "UPDATE cars SET miles = 50000 WHERE _id = 'abc123'"
    );
    ```

    ```dart Flutter - Legacy Query Builder (v4) theme={null}
    store.collection("cars")
        .findByID("abc123")
        .update((doc) {
            doc["miles"].set(50000);
        });
    ```
  </CodeGroup>

  **Observers:**

  <CodeGroup>
    ```dart Flutter - DQL Observer (v5) theme={null}
    store.registerObserver(
        "SELECT * FROM cars WHERE miles > 100000",
        (result) {
            // handle changes
        }
    );
    ```

    ```dart Flutter - Legacy Observer (v4) theme={null}
    store.collection("cars")
        .find("miles > 100000")
        .observe((docs, event) {
            // handle changes
        });
    ```
  </CodeGroup>

  <Note>
    Complete migration examples for all legacy query patterns are available in the [Legacy to DQL Migration Guide](/dql/legacy-to-dql-adoption).
  </Note>

  ***

  # Core Improvements

  ## Simplified Initialization & Configuration

  Ditto 5.0 introduces a completely redesigned initialization flow built around the new `DittoConfig` pattern. This replaces the previous `Identity`-based approach with a clearer, more predictable setup that aligns with modern best practices.

  ### What's New

  The new configuration system provides:

  * **Unified configuration object**: All initialization parameters are set through `DittoConfig` factory methods
  * **Fallible initialization**: Explicit error handling during setup catches configuration issues early
  * **Asynchronous patterns**: Native async/await support where appropriate for each platform
  * **Simplified authentication**: Clearer authorization client that's easier to understand and implement

  ### What This Solves

  The previous initialization flow required multiple unintuitive settings due to legacy compatibility concerns. For example, developers had to set `disableCloudSync = true` to connect to a Big Peer, which was confusing and non-obvious.

  The new pattern consolidates all configuration into a single, coherent flow that makes the relationship between settings explicit and easier to reason about.

  ### Accessing Configuration at Runtime

  After initializing Ditto, you can access the configuration object to retrieve settings like the database ID. This replaces methods like `getAppID()` from v4:

  ```javascript theme={null}
  // Example: Access database ID
  const config = ditto.config;  // or ditto.getConfig() depending on SDK
  const databaseID = config.databaseID;
  ```

  Each SDK provides access to the config object with language-appropriate naming conventions. See the SDK-specific migration guides for exact syntax.

  ### Availability

  The `DittoConfig` pattern was introduced as an option in v4.12 and becomes the only initialization method in v5.0.

  <Note>
    Migration guides for each SDK are available in the v5 documentation. If you're currently on v4.11 or later, the migration path is straightforward.
  </Note>

  ### Migration Example

  The initialization flow has changed from `Identity`-based to `DittoConfig`-based patterns. Here's how to migrate:

  <CodeGroup>
    ```dart Flutter - V5 theme={null}
    // Configure Ditto with server connection
    final config = DittoConfig(
        databaseID: 'your-database-id',  // was: appID
        connect: DittoConfigConnectServer(url: 'https://your-server.ditto.live')
    );
    final ditto = await Ditto.open(config);

    // Set up authentication
    await ditto.auth.setExpirationHandler((dittoAuth, timeUntilExpiration) async {
        final authResult = await dittoAuth.auth.login(
            token: 'your-token',
            provider: Authenticator.developmentProvider
        );
        if (authResult.exception != null) {
            throw authResult.exception!;
        }
    });

    await ditto.sync.start();  // was: ditto.startSync()
    ```

    ```dart Flutter - V4 theme={null}
    final identity = DittoIdentity.onlinePlayground(
        appID: "your-app-id",
        token: "your-token"
    );
    final ditto = Ditto(identity);

    await ditto.startSync();
    ```
  </CodeGroup>

  ### Accessing Configuration at Runtime

  After initialization, you can access your Ditto configuration to retrieve settings like the database ID:

  ```dart theme={null}
  final config = ditto.config;
  final databaseID = config.databaseID;  // Replaces ditto.appID from v4
  ```

  ## Schema-Free Data Modeling

  Ditto 5.0 transforms the developer experience by making DQL strict mode disabled by default. This eliminates the need to define collection schemas or CRDT types upfront, allowing you to insert nested objects and data structures without pre-defining types.

  ### What's New

  With strict mode disabled by default, Ditto changes how objects are stored and synchronized:

  **Objects default to MAP type instead of REGISTER type**

  This fundamental change means:

  * **Field-level sync**: Ditto syncs individual field changes instead of replacing entire objects
  * **Automatic type inference**: No need to pre-define collection schemas or CRDT types
  * **Nested structures**: Insert complex JSON-like documents without type definitions
  * **Concurrent updates merge**: When peers update different fields simultaneously, both changes are preserved

  For example, if two peers update different fields in the same object concurrently, both changes sync successfully rather than one overwriting the other.

  ### What This Solves

  This change provides a more simplified data management structure with two key benefits:

  * **Add-wins behavior on objects**: When peers create or modify objects, additions are preserved rather than overwritten
  * **Field-level delta sync on all nodes**: Every field in your document syncs independently, reducing bandwidth and enabling fine-grained conflict resolution throughout the entire document structure

  ### New Customers

  Schema-free data modeling is enabled by default in Ditto 5.0. No action is needed—simply start building with automatic type inference and field-level sync.

  ### Migrating Customers

  <Warning>
    If you're migrating from Ditto 4.X, set `DQL_STRICT_MODE = true` to ensure your application behavior remains the same:
  </Warning>

  ```sql theme={null}
  ALTER SYSTEM SET DQL_STRICT_MODE = true
  ```

  This maintains the same data modeling semantics you're currently using. Once your application is stable on v5, follow the strict mode migration guide and work with the Ditto CX team to migrate to schema-free data modeling and take advantage of the improved developer experience.

  ### Migration Considerations

  Strict mode is a **local configuration setting** on each device that controls how DQL interprets and writes data structures.

  **How it works across peers:**

  * Data **syncs successfully** between peers regardless of different strict mode settings
  * Each peer interprets data based on its **own** strict mode setting when reading/writing
  * With `DQL_STRICT_MODE=false`: Objects are inferred as MAPs (field-level merging)
  * With `DQL_STRICT_MODE=true`: Objects without explicit type definitions are treated as REGISTERs (whole object replacement)

  **Impact on data:**

  * Collections/documents created, modified, or read while strict mode is **disabled** will use inferred types (objects → MAPs by default)
  * Collections/documents created, modified, or read while strict mode is **enabled** use default REGISTER type and require explicit definitions for other types

  **Best practices for mixed deployments:**

  * If mixing settings, explicitly define MAP types in collection definitions on peers with strict mode enabled

  <Note>
    Learn more about strict mode, cross-peer synchronization, and troubleshooting in the [DQL Strict Mode documentation](/dql/strict-mode).
  </Note>

  ### How It Works

  The key difference is whether you need to explicitly define MAP types for objects:

  <CodeGroup>
    ```dart DQL_STRICT_MODE=false (Default in v5) theme={null}
    // Objects are automatically inferred as MAPs - no definition needed
    await store.execute("""
        INSERT INTO products
        DOCUMENTS ({
            _id: '123',
            name: 'Widget',
            metadata: {
                manufacturer: 'Acme Corp',
                warehouse: 'East'
            }
        })
    """);

    // Query without type definitions
    await store.execute("SELECT * FROM products WHERE _id = '123'");
    ```

    ```dart DQL_STRICT_MODE=true (Default in v4) theme={null}
    // Must explicitly define MAP types to use objects
    await store.execute("""
        INSERT INTO COLLECTION products (metadata MAP)
        DOCUMENTS ({
            _id: '123',
            name: 'Widget',
            metadata: {
                manufacturer: 'Acme Corp',
                warehouse: 'East'
            }
        })
    """);

    // Query with explicit MAP definition
    await store.execute("""
        SELECT * FROM COLLECTION products (metadata MAP)
        WHERE _id = '123'
    """);
    ```
  </CodeGroup>

  ## New DQL Query Features

  Ditto 5.0 introduces several new DQL syntax features that expand query capabilities and make complex queries easier to write.

  ### CASE Statements

  Add conditional logic to queries with CASE expressions:

  <CodeGroup>
    ```sql Simple CASE theme={null}
    -- Match a field against multiple values
    SELECT CASE a
      WHEN 1 THEN 'one'
      WHEN 2 THEN 'two'
      ELSE 'neither'
    END
    FROM test
    ```

    ```sql Searched CASE theme={null}
    -- Use conditional expressions
    SELECT CASE
      WHEN a = 1 THEN 'one'
      WHEN a = 2 THEN 'two'
      ELSE 'neither'
    END
    FROM test
    ```
  </CodeGroup>

  ### BETWEEN Expressions

  The `BETWEEN` operator provides a shorthand for defining an inclusive numeric range for an expression result.

  **Syntax:**

  ```sql theme={null}
  <expr> BETWEEN <low-expr> AND <high-expr>
  ```

  **Example:**

  ```sql theme={null}
  SELECT * FROM test WHERE a BETWEEN 1 AND 10
  ```

  This is equivalent to `(a >= 1 AND a <= 10)`.

  <Warning>
    **Order matters**: The order of expressions is important. Reversing the terms implies an inverse range - `BETWEEN 1 AND 10` and `BETWEEN 10 AND 1` are NOT equivalent.
  </Warning>

  ### Array & Object Search Syntax

  Test elements within arrays or objects using `ANY`, `EVERY`, or `ANY AND EVERY` operators:

  **Syntax:**

  ```sql theme={null}
  (ANY|EVERY|ANY AND EVERY) [name:] value (IN|WITHIN) expression SATISFIES condition END
  ```

  * **IN** - Searches the array/object directly
  * **WITHIN** - Searches recursively through nested structures
  * **ANY** - Returns true if at least one element matches
  * **EVERY** - Returns true if all elements match (empty arrays/objects pass)
  * **ANY AND EVERY** - Like EVERY, but empty arrays/objects fail

  <CodeGroup>
    ```sql Arrays theme={null}
    -- Check if any element in an array equals 2
    SELECT ANY x IN [1,2,3] SATISFIES x = 2 END
    FROM system:dual

    -- Check if any nested element equals 2
    SELECT ANY x WITHIN [1,[2],3] SATISFIES x = 2 END
    FROM system:dual

    -- Check if all elements equal 1 (or are arrays)
    SELECT EVERY x WITHIN [1,[1],1]
    SATISFIES x = 1 OR type(x) = 'array' END
    FROM system:dual
    ```

    ```sql Objects theme={null}
    -- Check if any field value equals 2
    SELECT ANY x IN {'a':1,'b':2,'c':3} SATISFIES x = 2 END
    FROM system:dual

    -- Check if any nested field value equals 2
    SELECT ANY x WITHIN {'a':1,'b':{'d':2},'c':3} SATISFIES x = 2 END
    FROM system:dual
    ```

    ```sql Practical Examples theme={null}
    -- Find documents where first array element is less than zero
    SELECT * FROM test
    WHERE ANY n:v IN test.array_field SATISFIES n = 0 AND v < 0 END

    -- Find documents where any nested field is NULL
    SELECT * FROM test
    WHERE ANY v WITHIN test.details SATISFIES v IS NULL END

    -- Find orders where items were modified after order date
    SELECT * FROM orders o
    WHERE ANY v IN o.items SATISFIES v.modified > o.order_date END
    ```
  </CodeGroup>

  ### Array & Object Transformation Syntax

  Create new arrays and objects by transforming existing data structures:

  **Array Transformation Syntax:**

  ```sql theme={null}
  ARRAY valueExpr FOR [name:] value IN source [WHEN condition] END
  ```

  **Object Transformation Syntax:**

  ```sql theme={null}
  OBJECT nameExpr:valueExpr FOR name:value IN source [WHEN condition] END
  ```

  <CodeGroup>
    ```sql Array Transformations theme={null}
    -- Transform array elements to objects with index
    ARRAY {"index":i,"val":v} FOR i:v IN [1,2,3] WHEN v%2 = 0 END
    -- Result: [{"index":1,"val":2}]

    -- Convert numbers to strings, excluding value 1
    ARRAY cast(v,'string') FOR v IN [1,2,3] WHEN v != 1 END
    -- Result: ["2","3"]

    -- Transform string characters with conditional logic
    ARRAY CASE WHEN i%2 = 0 THEN "foo" ELSE "bar" END
    FOR i:v IN split("hello","") END
    -- Result: ["foo","bar","foo","bar","foo","bar"]

    -- Extract values from object into array
    ARRAY v FOR n:v IN {"a":"one","b":"two"} END
    -- Result: ["one","two"]
    ```

    ```sql Object Transformations theme={null}
    -- Transform object keys to uppercase, filter by value length
    OBJECT upper(n):v FOR n:v IN {"a":"one","b":"two","c":"three"}
    WHEN len(v) = 3 END
    -- Result: {"A":"one","B":"two"}

    -- Convert array to object with generated field names
    OBJECT "field_"||cast(i,"string"):v FOR i:v IN [1,2,3] END
    -- Result: {"field_0":1,"field_1":2,"field_2":3}

    -- Filter object by value type
    OBJECT n:v FOR n:v IN {"a":1,"b":[],"c":2}
    WHEN type(v) != 'array' END
    -- Result: {"a":1,"c":2}
    ```
  </CodeGroup>

  **Key behaviors:**

  * If `source` evaluates to `MISSING`, the result is `MISSING`
  * For arrays: if `source` is not an array/object, the result is `NULL`
  * For objects: duplicate field names will overwrite previous values
  * Elements/fields where `valueExpr` evaluates to `MISSING` are excluded from the result

  ### Extended String Literals

  Support for escape sequences in strings:

  ```sql theme={null}
  -- Use escape sequences in string literals
  SELECT * FROM messages
  WHERE content = 'Line 1\nLine 2\tTabbed'

  -- [PLACEHOLDER: Add more escape sequence examples if needed]
  ```

  ### Hexadecimal Numeric Constants

  Additional numeric literal formats:

  ```sql theme={null}
  -- Use hexadecimal literals
  SELECT * FROM config
  WHERE flags = 0xFF

  -- [PLACEHOLDER: Add more hex literal examples if needed]
  ```

  ***

  # Performance & Platform

  ## DQL Query Performance Improvements

  Your applications will feel noticeably faster and more responsive. Data queries complete faster, delivering a snappier user experience whether users are searching, filtering, or loading content. These performance gains happen automatically—no code changes required.

  ### Query Planner Enhancements

  The DQL query planner has been enhanced to recognize more optimization opportunities:

  * **Automatic ID scan conversion**: Equality filters on `_id` fields automatically convert to ID scans, bypassing index lookups when exact document IDs are known
  * **Deferred document fetching**: Query planner can defer fetching full documents until after sorting and applying offset/limit when index access supports it
  * **Improved covering index support**: More scenarios where the query planner can satisfy queries entirely from index data without retrieving documents
  * **Index-only queries**: Additional cases where queries can be answered using only index scans

  ### Streaming Query Execution

  The query engine now uses streaming interfaces internally:

  * **Reduced memory overhead**: Results are streamed rather than fully materialized where possible
  * **DISTINCT operator streaming**: DISTINCT queries now stream results, reducing memory usage for large result sets
  * **Improved operator inlining**: Query operators can be inlined into producers for better performance

  ### Shared Statement Cache

  Ditto 5.0 introduces a shared statement cache that stores and reuses compiled query plans:

  * **Plan reuse**: Compiled query plans are cached and reused for identical or similar statements, eliminating redundant parsing and planning overhead
  * **Automatic validation**: Cached plans are automatically verified and invalidated when collection schemas or system directives change
  * **Dynamic sizing**: The cache automatically resizes based on workload patterns
  * **Improved large statement performance**: Particularly benefits complex queries and larger statements by avoiding expensive re-compilation

  This optimization is especially impactful for applications that execute the same queries repeatedly, such as real-time dashboards or frequently-accessed data views.

  <Note>
    These improvements are automatic - no code changes required. Your existing DQL queries will benefit from the enhanced query planner.
  </Note>

  ## Data Sync Performance Improvements

  Building on the performance improvements delivered in v4.13 & v4.14, Ditto 5.0 further optimizes data synchronization through tiered blob storage and protocol enhancements, making sync operations faster and more efficient.

  ### What's New

  Version 5.0 introduces:

  * **Tiered blob storage**: Smaller sync updates avoid unnecessary disk I/O by using optimized storage tiers
  * **Improved session handling**: Better avoidance of session resets on reconnection when in-flight updates were lost
  * **Optimized fsync policy**: Document sync avoids forcing files to disk by default, decreasing I/O and improving latency

  ### Impact

  Applications upgrading to v5.0 will experience:

  * **Faster sync operations**: Reduced disk I/O overhead leads to quicker data synchronization
  * **Lower latency**: Optimized file handling decreases sync latency across the board
  * **Better reconnection handling**: Fewer redundant updates after temporary disconnections
  * **Improved efficiency**: Reduced disk operations lower memory and CPU pressure during sync

  ## Local System Observability

  Gain unprecedented visibility into how Ditto operates on your devices. Query real-time metrics, inspect runtime configuration, and monitor system health directly using DQL—giving you deeper insights than ever before to debug issues, optimize performance, and understand your application's behavior.

  ### New Virtual Collections

  **`system:metrics`**

  * Query performance metrics and diagnostics in real-time
  * Access counters, timers, and other operational metrics via DQL
  * Monitor system health and performance without external tools

  **`system:system_info`**

  * Query `peer_key`, `database_id`, and configuration settings
  * Inspect runtime configuration and system parameters
  * Useful for debugging and operational awareness

  **`system:shared_statements`**

  * Inspect the query plan cache
  * View cached statements and their execution plans
  * Supports DELETE operations to clear specific cached statements
  * Helps optimize query performance and troubleshoot query planning

  <Note>
    **Local-Only Collections**: System collections are local to each peer and are **not replicated** across the mesh. To query these collections on remote peers, use [Remote Query](https://docs.ditto.live/cloud/common/operations/remote-query) from the Ditto Portal.
  </Note>

  ### Usage Example

  ```sql theme={null}
  -- Query system information
  SELECT * FROM system:system_info

  -- View cached query statements
  SELECT * FROM system:shared_statements

  -- Access metrics
  SELECT * FROM system:metrics
  WHERE metric_name = 'sync.documents_synced'

  -- Clear a specific cached statement
  DELETE FROM system:shared_statements
  WHERE statement_id = 'abc123'
  ```

  These collections provide unprecedented visibility into Ditto's internal state, making it easier to monitor, debug, and optimize your applications.

  ## Additional Improvements

  ### Reliability & Error Handling

  * **Enhanced diagnostics**: Improved logging when peers receive data that cannot be deserialized
  * **Recovery mechanisms**: Additional recovery paths for document deserialization errors
  * **Smart log levels**: Connection failures start at warning level, escalate to error only after repeated failures
  * **Panic messages**: Filtered to remove internal Rust machinery frames for improved readability

  ### Networking Improvements

  * **Graceful shutdown**: Network connections close cleanly when Ditto is stopped
  * **Faster disconnection detection**: When a peer crashes, Ditto stops attempting to connect within 15 seconds (previously up to 75 minutes)
  * **mDNS improvements**: More reliable mDNS discovery, configurable service names, better address filtering
  * **BLE improvements**: Fixed connection issues on Android 9 and earlier devices
  * **WebSocket BYOD support**: Bring Your Own Discovery now supports WebSocket connections
  * **Connection cleanup**: Fixed deadlock where devices could fail to establish new P2P connections until restarted

  ### DQL Engine Improvements

  Beyond the query performance improvements detailed above, v5 includes:

  * **Better error messages**: Improved parser error messages for invalid DQL syntax
  * **Transaction safety**: Fixed deadlock scenarios in concurrent transactions
  * **Index correctness**: Fixed issues where index scans could yield incorrect results on document deletion

  ### Logging & Diagnostics

  * **Better disk utilization**: On-disk logs resume writing to incomplete files, making better use of available space
  * **Compressed size limits**: Log file limits now apply to compressed size, significantly increasing retention
  * **Explicit flushing**: Logs explicitly flushed before aborting due to panic
  * **Virtual collections**: New `system:metrics` and `system:system_info` collections for DQL access to metrics and system information

  ### Platform Support

  * **Linux aarch64**: Kotlin SDK now supports ARM64 Linux (Raspberry Pi, AWS Graviton, etc.)
  * **Swift 6**: Full Swift 6 support with Sendable conformance
  * **16KB alignment**: React Native Android meets Google Play's November 2025 requirement

  ***

  # Upgrading to v5

  ### Flutter Migration Guide

  Upgrading to Ditto 5.0 requires updating your initialization code and migrating from legacy query APIs to DQL. The migration process involves:

  * Updating from `DittoIdentity` to `DittoConfig`-based initialization
  * Replacing legacy query builder operations with DQL statements
  * Migrating collection observers to DQL observers
  * Updating authentication patterns

  For comprehensive migration instructions, code examples, and best practices, see the [Flutter v4 to v5 Migration Guide](/sdk/latest/migration-guides/flutter-v4).

  ## Terminology Updates

  Ditto 5.0 updates terminology across the platform to align with industry standards and reduce confusion.

  ### Database ID (formerly App ID)

  * `appID` → `databaseID` in all configuration methods
  * `getAppId()` → `getConfig().databaseId` in SDK APIs
  * Portal and documentation updated to use "Database ID" terminology

  **Why this matters**: The term "App ID" caused confusion, particularly for mobile developers who associate "app" with the mobile application itself rather than the Ditto database instance. "Database ID" more accurately describes what the identifier represents: a unique identifier for your Ditto database that persists across all clients.

  ### Ditto Server (formerly Ditto Cloud)

  * `isConnectedToDittoCloud` → `isConnectedToDittoServer` in presence APIs
  * Documentation updated to use "Ditto Server" terminology

  **Why this matters**: This clarifies that the property indicates connection to any Big Peer (Ditto Server), not just those running in Ditto's cloud service. This is more accurate for deployments using self-hosted Big Peers.

  ### Migration

  Update your code to use the new terminology:

  <CodeGroup>
    ```dart Flutter - New Terminology (v5) theme={null}
    // Database ID
    final config = DittoConfig.onlinePlayground(
        databaseID: "your-id",  // was: appID
        token: "your-token"
    );

    // Presence API
    if (peer.isConnectedToDittoServer) {
        // handle connection
    }
    ```

    ```dart Flutter - Old Terminology (v4) theme={null}
    // App ID
    final identity = DittoIdentity.onlinePlayground(
        appID: "your-id",
        token: "your-token"
    );

    // Presence API
    if (peer.isConnectedToDittoCloud) {
        // handle connection
    }
    ```
  </CodeGroup>

  The actual ID values and functionality remain unchanged - only the parameter and property names have been updated.

  ## Breaking Changes

  Ditto 5.0 is a major version release that removes deprecated APIs and legacy features. For migration guidance, see [Migration Guidance](#v5-migration-guidance).

  ### Removed APIs

  #### Legacy Query Builder (All SDKs)

  All legacy query builder APIs have been removed:

  * `store.collection()` → Use DQL `INSERT`, `UPDATE`, `EVICT` statements
  * `collection.find()` → Use DQL `SELECT` queries
  * `collection.findById()` → Use DQL with `_id` filter
  * Live queries → Use DQL observers with `store.registerObserver()`
  * Write transactions → Use DQL `store.write()` with transactions

  #### Legacy Initialization (All SDKs)

  * `Identity` classes and all subclasses removed
  * `Ditto(identity:, persistenceDirectory:)` constructors removed
  * Use `DittoConfig` factory methods and `Ditto.open()` instead

  #### Sync Methods Moved

  * `ditto.startSync()` → `ditto.sync.start()`
  * `ditto.stopSync()` → `ditto.sync.stop()`
  * `ditto.isSyncActive` → `ditto.sync.isActive`

  #### Other Removals

  * `disableSyncWithV3()` - no longer needed, v3 sync removed entirely
  * `AttachmentToken` - use dictionary variant
  * Transport diagnostics APIs - obsolete, removed
  * Various deprecated presence properties (`queryOverlapGroup`, `meshRole`, etc.)
  * Emoji log level headings - setting had no effect, removed

  ### Behavioral Changes

  Several default behaviors have changed in v5:

  * **DQL strict mode**: Now defaults to `false` - no schema definitions required, automatic CRDT type inference
  * **String literals in DQL**: Double quotes now delimit strings (not identifiers) for JSON compatibility
  * **Subscription queries**: Reject `LIMIT` and `ORDER BY` unless `DQL_RESTRICT_SUBSCRIPTION=false`
  * **Observer ordering**: Observers require explicit `ORDER BY` clause for stable ordering
  * **WebSocket sync**: Disabled by default in new `TransportConfig` instances - must explicitly enable
  * **Document IDs**: `null` is no longer allowed as a document ID

  <Note>
    These behavioral changes may affect existing code. Review your DQL queries and subscription logic when migrating to v5.
  </Note>

  ### SDK Size Reduction

  The removal of legacy APIs has reduced SDK footprint by approximately 25%, resulting in:

  * Smaller application binary sizes
  * Reduced memory usage
  * Faster SDK initialization
  * Simpler maintenance and debugging

  ***

  # Flutter Specific Changes

  ## Flutter-Specific Changes

  The Flutter SDK has additional platform-specific changes in v5.0 beyond the common breaking changes.

  ### Breaking: Resource Management

  **Manual Cleanup Required:**

  * All classes that manage resources must now be manually freed
  * This standardizes finalization across the SDK
  * Ensures proper resource cleanup and prevents leaks

  ### API Changes

  **Store Observer:**

  * `StoreObserver.changes` is now a single-subscription stream (previously multi-subscription)

  **Query Arguments:**

  * `SyncSubscription.queryArguments` no longer guaranteed to be strictly equal to original arguments due to serialization roundtrip
  * Added `queryArgumentsCborBytes` and `queryArgumentsJsonString` properties for custom decoding

  **Transactions:**

  * Throwing in a transaction scope now correctly rolls back the transaction

  **Transport Config:**

  * `TransportConfig` types are now immutable and `const`
  * Added builder types for mutable configuration
  * `ditto.updateTransportConfig` callback parameter now takes `TransportConfigBuilder` instead of `TransportConfig`

  **Config & Identity:**

  * Added `DittoConfig` class to encompass all initialization data
  * `Ditto.open` now takes optional `DittoConfig` instead of `Identity` and `persistenceDirectory`
  * Added `ditto.auth.expirationHandler` - callback for when authorization is expiring
  * Removed `AuthenticationHandler` - Use `ditto.auth.expirationHandler` instead
  * Removed `Identity` and all subtypes - Use `DittoConfig` instead

  **Presence:**

  * Added more ergonomic APIs for interacting with `PresenceGraph` and related types

  **Document IDs:**

  * Removed `DocumentID` class from public API
  * Document IDs now returned as raw JSON values (`dynamic` type) instead of wrapped in `DocumentID` class
  * `QueryResult.mutatedDocumentIDs()` now returns `List<dynamic>` instead of `List<DocumentID>`
  * Document IDs can be any JSON-compatible type: strings, integers, booleans, null, lists, or maps

  **Peer & Connection Properties:**

  * Removed `Peer.peerKeyString` - Use `Peer.peerKey` instead
  * Removed `ConnectionRequest.peerKeyString` - Use `ConnectionRequest.peerKey` instead
  * Removed `Connection.peerKeyString1` - Use `Connection.peer1` instead
  * Removed `Connection.peerKeyString2` - Use `Connection.peer2` instead

  **Logging:**

  * Removed `setLogFile()` method - Use `exportLogs()` instead

  **Small Peer Info:**

  * Removed `SmallPeerInfoSyncScope` and `syncScope` property

  **Authentication:**

  * Added `Authenticator.developmentProvider` constant for sandbox identity providers
  * Removed `siteID` from identity APIs

  ### Performance Improvements

  **Store Operations:**

  * `ditto.store.execute` calls now offloaded to background isolates on VM platforms
  * Makes store operations non-blocking

  ### Bug Fixes

  * Fixed memory safety bug that caused sporadic use-after-free errors (#18504)
  * Fixed race condition in `StoreObserver` that could throw when cancelling while callbacks are arriving (#SDKS-2494)
  * Fixed `DittoError` being thrown where `DittoException` should have been thrown (#16925)

  ***

  # Full Changelog

  <AccordionGroup>
    <Accordion title="Flutter Specific Changes">
      ## Flutter Specific Changes

      <Icon icon="screwdriver-wrench" iconType="solid" horizontal /> **Fixed**:

      * Several places where `DittoError` was thrown where `DittoException` should have been thrown (#16925)
      * Standardized finalization so that all classes that manage resources must now be manually freed (#17275)
      * Throwing in a transaction scope will now correctly rollback a transaction (#17808)
      * Memory safety bug that can caused sporadic use-after-free errors (#18504)
      * A race condition in `StoreObserver` that could throw when cancelling an observer while callbacks are still arriving (#SDKS-2494)
      * History tracking is now correctly disabled by default. Previously, the Flutter SDK unintentionally enabled history tracking, causing the `__history` local-only collection to grow without bound. Apps that used a previous version of the Flutter SDK should execute `EVICT FROM __history` during app initialization to purge accumulated history data (#SPO-650)

      <Icon icon="rotate-reverse" iconType="solid" horizontal /> **Changed**:

      * `StoreObserver.changes` is now a single-subscription stream
      * The `queryArguments` property on `SyncSubscription`s is no longer guaranteed to be strictly equal to the original arguments passed when registering the sync subscription. This is due to a serialization roundtrip, which may affect equality checks, particularly for non-primitive values. If you want to decode query arguments into a specific type, then use the `queryArgumentsCborBytes` or `queryArgumentsJsonString` properties now available on `SyncSubscription` instances and decode things as required (#17003)
      * `TransportConfig` types are now immutable, `const`, and have builder types (#17876)
      * `ditto.updateTransportConfig`'s callback parameter now takes a `TransportConfigBuilder` instead of a `TransportConfig` (#17876)
      * `Ditto.open` now takes an optional `DittoConfig` instead of an `Identity` and `persistenceDirectory` (#17937)
      * Offloads `ditto.store.execute` calls to background isolates to make them non-blocking on VM platforms (#18455)
      * `QueryResult.mutatedDocumentIDs()` now returns `List<dynamic>` instead of `List<DocumentID>`. Document IDs can be any JSON-compatible type: strings, integers, booleans, null, lists, or maps (#SDKS-1166)

      <Icon icon="plus" iconType="solid" horizontal /> **Added**:

      * `queryArgumentsCborBytes` and `queryArgumentsJsonString` properties to `SyncSubscription` instances. If you want to decode query arguments into a specific type, then use these and decode things as required (#17003)
      * `DittoConfig` class to encompass all data needed to initialize a `Ditto` instance (#17937)
      * `ditto.auth.expirationHandler` - a callback that is called when authorization is expiring (#17937)
      * More ergonomic APIs for interacting with `PresenceGraph`, and related types (#17954)
      * `Authenticator.developmentProvider` constant for use with sandbox identity providers (#SDKS-2594)

      <Icon icon="bin-recycle" iconType="solid" horizontal /> **Removed**:

      * `setLogFile()` method. Use `exportLogs()` instead (#19399)
      * `SmallPeerInfoSyncScope` and `syncScope` property (#19402)
      * `DocumentID` class has been removed from the public API. Document IDs are now returned as raw JSON values (dynamic type) instead of being wrapped in a DocumentID class (#SDKS-1166)
      * `Peer.peerKeyString`. Use `Peer.peerKey` instead (#SDKS-1182)
      * `ConnectionRequest.peerKeyString`. Use `ConnectionRequest.peerKey` instead (#SDKS-1182)
      * `Connection.peerKeyString1`. Use `Connection.peer1` instead (#SDKS-1182)
      * `Connection.peerKeyString2`. Use `Connection.peer2` instead (#SDKS-1182)
      * Legacy identity configuration APIs are no longer supported in Ditto v5 (#SDKS-2435)
      * `AuthenticationHandler` - please use `ditto.auth.expirationHandler` instead (#17937)
      * `Identity` and all subtypes - please use `DittoConfig` instead (#17937)
      * `siteID` from identity APIs (#SDKS-696)
    </Accordion>

    <Accordion title="Common Changes">
      ## 5.0.0 Common Changelog

      <Icon icon="rabbit-running" iconType="solid" horizontal /> **Performance**:

      * Improved the underlying representation of Ditto documents for better performance (#17509)
      * Document synchronization between peers now batches updates more efficiently, reducing processing time for large document sets (#19273)
      * Document sync avoids sending large, redundant updates after reconnecting a long-dormant session between two peers that are otherwise well-synced with the mesh (#DS-433)
      * Improved avoidance of large redundant doc sync updates after session reconnect, based on the number of diffs sent in the initial post-reconnect update (#DS-475)
      * Faster initial sync when processing rkyv-encoded document diffs (#DS-773)
      * Faster eviction of indexed documents when using rkyv (#DS-774)
      * Improved performance of initial index generation when using rkyv as a document format (#DS-774)
      * Reduced redundant replication GC work during rapid eviction bursts by debouncing and coalescing compatible GC tasks (#CORE-1466)
      * Synchronization protocol enhanced to better avoid resetting sessions on reconnect if in-flight updates were lost (#DS-820)
      * Document Sync now uses tiered blob store for update file storage by default, allowing smaller updates to avoid unnecessary disk I/O (#DS-836)
      * Document sync implementation avoids forcing outbound update files to disk by default, decreasing disk I/O and improving sync latency (#DS-921)
      * Observers to avoid sort by id on non order by query / add limit to sort operator (#QE-261)
      * Improved out-the-box performance for larger statements (#QE-377 & QE-378)
      * Improved the performance of IN-list evaluation for large lists of static values (#QE-386)

      <Icon icon="screwdriver-wrench" iconType="solid" horizontal /> **Fixed**:

      * An issue with BLE on some Android 9 and earlier devices that prevented connection establishment (#17760)
      * Multiple concurrent DQL transactions can no longer possibly lead to a deadlock (#17816)
      * A bug where x509 refresh could speed up uncontrollably (#17947)
      * A bug where a peer could get stuck with incorrect connection information (#17967)
      * Network connections close gracefully when Ditto is stopped (#18053)
      * The `system:data_sync_info` collection may briefly report sync immediately after connecting (#18137)
      * An issue where peers could fail to connect other local peers via mDNS on macOS (#18488)
      * A bug that meant that document id indexes were not created (#18512)
      * A bug where forced TCP connections would be retried more frequently than expected (#19727)
      * A bug where mDNS registration would fail with `NamingConflict` (#20411)
      * mDNS discovery should support TCP and UDP independently (#20490)
      * Connection manager now correctly cleans up orphaned connecting state when tasks are cancelled during shutdown (e.g., during auth refresh), preventing "Already connecting" errors on reconnection (#20377)
      * A deadlock could occur where a device would fail to establish new P2P connections until restarted (#20810)
      * A race condition where `fetchAttachment` could permanently fail to find locally-created attachments due to stale in-memory cache entries (#21146)
      * A bug that caused small peers to re-upload remotely requested files (e.g. logs) on every startup (#CORE-810)
      * High latency when write transactions trigger evictions (#CORE-1453)
      * Live queries being unable to use indices (#DS-447)
      * A rare scenario where an attachment fetch could be delayed by up to 60 seconds (#DS-461)
      * Deadlock in sync session metadata cleanup caused cascading lockups for doc sync and/or local doc store access (#DS-485)
      * Post eviction cleanup of disconnected document sync sessions now retains metadata for non-evicted documents (#DS-487)
      * Document sync session metadata became unlinked after session reset (#DS-509)
      * DQL SELECT queries on indexed collections could deadlock if executed in an explicit transaction (#DS-648)
      * DQL queries using indexes could yield wrong results upon document deletion (#DS-851)
      * Inconsistent internal hashing of Document IDs could cause failure to sync documents (#DS-944)
      * Premature connection cleanup causing duplicate connections (#NETW-1021)
      * When another peer crashes, Ditto will stop attempting to connect to it in under 15 seconds. Previously, connection attempts would occur for up to 75 minutes at 5 second intervals (#NETW-856)
      * Changed live queries to use the new streaming interface for query execution (#QE-261)
      * Use of DISTINCT with ORDER BY & OFFSET/LIMIT (#QE-281)
      * In BP profile directive does not produce path in collection scan operator profile (#QE-294)
      * Handling of references to group keys that include array element selection (#QE-306)
      * Use deterministic summaries for documents created as part of observer evaluation (#QE-310)
      * Removed fabricated descriptor information from collection scans in profile/explain information (#QE-315)
      * Performance of the DQL parser for large statements (#QE-321)
      * DQL duration function floating-point rounding errors (#QE-402)
      * Incorrect association of terms following an `IN expr` clause (#QE-418)
      * Executing index scans in observers preserves document ids to provide consistent ordering (#QE-429)
      * The query planner misses using a Filter operator if collection scan filter pushdown is enabled (#QE-437)
      * Small peer collection scan handles offset and limit incorrectly (#QE-438)
      * Changed DQL planner index selection process to correctly handle predicate paths that haven't been formalised avoiding incorrect index selection (#QE-456)
      * The DQL query planner will no longer generate index scans on fields which have been specified in a COLLECTIONS clause as the variant specified may differ from the indexed variant. This prevents incorrect query results arising from the mismatch (#QE-475)
      * The small peer DQL query planner to not produce index scans when DQL\_STRICT\_MODE is set to true. This avoids incorrect results from filters on fields where the latest variant is not REGISTER (#QE-478)
      * The store SQLITE logging callback has been changed to not report schema change errors avoiding flooding the logs with spurious warnings from SQLITE internal operations (#QE-479)
      * A panic in the DQL parser when an invalid JSON directive is used prior to the PROFILE keyword (#QE-490)
      * -9223372036854775808 is now parsed and handled as an integer value by DQL (#QE-499)
      * Queries in the legacy language might fail to surface documents with settable counters (#QE-512)
      * Documentation for on-disk logger incorrectly stated logs are retained for 3 days; actual retention is 15 days (#SDKS-1726)
      * FFI resource cleanup now safely handles null context pointers in release callbacks, preventing potential null pointer dereferences during Ditto shutdown (#SDKS-2744)
      * Attachment callback dispatch now properly handles thread pool dispatch failures by retaining context to prevent use-after-free errors when the callback pool is unavailable (#SDKS-2744)
      * Transport watchdog no longer logs spurious "Address already in use" errors when restarting TCP/HTTP servers. The watchdog now waits for previous server tasks to fully exit and release their sockets before attempting to rebind ports, preventing EADDRINUSE races when servers are invalidated during e.g. app backgrounding (#SPO-127)
      * Attachment garbage collection now removes empty shard directories, preventing inode leaks (#SPO-158)
      * Bug which meant a Ditto starting log failed to be logged (#SPO-626)
      * Android devices that fail to acquire an IP address will now continue to sync over LAN (#TRAN-725)
      * A long-running on connecting callback no longer causes `ReceiveTimeout` failures in connectivity (#TRAN-729)

      <Icon icon="rotate-reverse" iconType="solid" horizontal /> **Changed**:

      * `network_enable_multihop` system parameter renamed to `network_enable_ngn`, gating NGN features which include multihop (#17882)
      * Enabled opentelemetry tracing in core (#18478)
      * Connection failures now use smart log levels, starting at warning and escalating to error only after repeated failures (#18779)
      * mDNS now only advertises connectable addresses based on TCP server binding address. TCP Client now attempts to connect to all addresses in parallel (#18930)
      * The default value of `ENABLE_ATTACHMENT_PERMISSION_CHECKS` store configuration parameter to `false` (#18931)
      * mDNS service name is now configurable via the `transports_mdns_service_name` SystemParameter (default: `_http-alt`), ensuring both TCP and UDP transports use the same service name (#20289)
      * Panic messages now filter out internal Rust machinery frames (backtrace capture, panic handling, runtime startup) for improved readability, with an environment variable `DITTO_PANIC_WITH_FULL_STACK_TRACE=1` available to show complete stack traces when needed (#20401)
      * On-disk logs now make better use of available disk space by resuming writing to incomplete files (#CORE-561)
      * On-disk log file limits now apply to the compressed size, significantly increasing log retention (#CORE-729)
      * Write transaction diagnostic logs now include the blocking transaction's current operation, elapsed time, and queue depth (#CORE-1449)
      * More information is logged at debug level around peer GC and eviction progress including what remote peers are being deleted (#CORE-1455)
      * Significantly lowered the maximum values of some system parameters governing the on-disk rotating file logger's behavior (#CORE-848)
      * More information is logged when a Ditto peer receives data that it cannot deserialize due to a hash mismatch (#CORE-897)
      * We now make an additional attempt to recover from some kinds of document deserialization errors, which may reduce errors or crashes due to deserialization (#CORE-916)
      * Document sync protocol now supports rkyv-encoded diffs, for more efficient initial synchronization (#DS-531)
      * TCP server is no longer auto-enabled when TCP is disabled in config, NGN and UDP is enabled with LAN discovery (#NETW-1039)
      * Mutators are preserved for Big Peer V4 (#QE-126)
      * Disallow null as an id (#QE-202)
      * DQL\_STRICT\_MODE default to false (#QE-267)
      * Planning for statements using DISTINCT projections, in some circumstances (#QE-282)
      * system:vitals outputs timers as sub-document (#QE-312)
      * DQL queries run via observers now require that the user provides stable ordering themselves via a suitable ORDER BY clause (#QE-427)
      * Double quotes delimit strings, not identifiers (JSON compatibility) (#QE-44)
      * DQL query planner now recognises additional index access plans that eliminate the need for document retrieval (#QE-449)
      * Added the key sorting direction to the `system:indexes` virtual collection output (#QE-467)
      * The DQL planner to automatically convert equality filters on the `_id` field to ID scans, improving performance by skipping index use when exact document IDs are known up front (#QE-469)
      * The DQL query planner can now create a query plan that defers fetching full documents until after sorting and application of offset and limit, if the index access portion of the plan can support it. This means performance improvements for queries with affected plans (#QE-473)
      * Revised the Query Engine DISTINCT operator to stream results reducing memory overhead (#QE-474)
      * The DQL planner to consider additional cases where an index may cover a query leading to improved performance in those scenarios (#QE-491)
      * The DQL Query Engine planner can now produce specialised higher performance plans for Ditto Server `COUNT(*)` queries that include simple filters (#QE-510)
      * The Query Engine DQL planner can now generate index-access plans against Ditto Server improving performance queries with filters that can be applied when scanning an index and where combining multiple index scans is beneficial (#QE-511)
      * The Query Engine intersect scan operator can now stop before all inputs have completed, once it has been established that no further complete intersections can be produced, improving the performance where the number of values produced by each input differs greatly (#QE-530)
      * Added specialisation of simple queries to take advantage of small peer indexing (#QE-266)
      * Added support for microseconds to duration scalar functions (#QE-396)
      * Removed the Parseable query trait to minimise the impact of the query parser maintenance on the monorepo (#QE-421)
      * System collection `system:ditto_metrics` renamed to `system:metrics` for consistency with naming conventions. Existing queries using `system:ditto_metrics` will need to be updated to use `system:metrics` (#SDKS-2653)
      * Ditto shutdown logging promoted to info level (#SPO-626)

      <Icon icon="plus" iconType="solid" horizontal /> **Added**:

      * `ENABLE_ATTACHMENT_PERMISSION_CHECKS` ALTER SYSTEM parameter to be set to `false` to avoid certain rare cases of attachment fetcher hanging (#18016)
      * Bring Your Own Discovery now supports WebSocket connections (#18965)
      * `system:metrics` virtual collection for DQL access to metrics (#MESHCON-53)
      * Introduced new entries to the `system:system_info` collection for `peer_key` and `database_id` (#19435)
      * `DATA_SYNC_ENABLED` system parameter which, while set to `false`, halts the data sync machinery, but without loss of network connectivity (allowing for operations such as remote query) (#19643)
      * `DITTO_USE_TIERED_BLOB_STORE_DOC_SYNC` system parameter env var to improve the performance of doc sync in heavy mesh scenarios, at the expense of sync chatter overhead upon restart (#19847)
      * The new `transport_tcp_connect_timeout` system parameter which shortcuts long platform-based TCP connection timeouts (#20782)
      * Explicit log flushing before aborting due to panic (#CORE-723)
      * `system:system_info` virtual collection for DQL access to system info (#CORE-751)
      * small\_peer\_info subscription queries now include arguments (#DS-1027)
      * system:system\_info subscription queries now include arguments; query location moved from key to value.query (#DS-1027)
      * Improved logging for document deserialization errors (#DS-568)
      * System parameters that can be used to configure sqlite pragmas (#DS-682)
      * System parameter `doc_sync_outbound_update_fsync_policy` to govern the use of fsyncs when creating doc sync update files (#DS-817)
      * Channel open retries and watchdog to tear down VirtualConnections that never open a channel, preventing resource exhaustion from stalled peers (#NETW-1098)
      * A system parameter `transports_dns_sd_backend` for choosing the mDNS backend implementation (#NETW-940)
      * Ability to specify documents to insert in arrays in DQL (#QE-118)
      * USE IDS LIST syntax (#QE-119)
      * Support for settable counters to DQL (#QE-130, QE-393, QE-394, QE-395)
      * Specialisation of COUNT(\*) DQL queries on the big peer (#QE-138)
      * Subscription queries reject LIMIT and ORDER by unless DQL\_RESTRICT\_SUBSCRIPTION is set to false (#QE-218)
      * INTERSECT and UNION (index) scans (#QE-230\_and\_240)
      * Covering index scans (#QE-239)
      * Support for the BETWEEN DQL expression (#QE-26)
      * Streaming interfaces for query execution (#QE-262)
      * Array & object search syntax to DQL (#QE-265)
      * Ability to inline consumers into producer operators (#QE-272)
      * Consolidated results across subservers for queries against ACTIVE\_REQUESTS, REQUEST\_HISTORY and VITALS (#QE-273)
      * Array transformation DQL syntax (#QE-274)
      * Object transformation syntax to DQL (#QE-276)
      * Promethus metrics to the DQL Query engine (#QE-296)
      * Automatic generation of USE IDS clause from \_id equality predicates when possible (#QE-313)
      * A shared statement cache and virtual collection (#QE-316)
      * Configurable concurrent request limit to the Query engine (#QE-317)
      * Periodic dumping of request history cache entries to the log (SP only) (#QE-322)
      * The ability for the shared statement to store, verify, amend and use existing plans for qualifying statements (#QE-324)
      * PROFILE keyword as the equivalent to the #profile directive (#QE-336)
      * CASE statement (#QE-41)
      * Support for settable counters in INSERT DQL statements (#QE-406)
      * The statement caches invalidates existing statements if the default directives change (#QE-407)
      * Support for extended string literals that can contain escape sequences in DQL (#QE-410)
      * Support for hexadecimal numeric constants in DQL statements (#QE-413)
      * Statement cache resizing (#QE-414)
      * The ability for Remote Query to handle DELETE, EVICT, TOMBSTONE DQL statement (#QE-441)
      * Enable sending all statements via the SYNC CONTEXT statement (#QE-447)
      * Support for DQL DELETE against the `system:shared_statements` virtual collection (#QE-450)
      * Publish sync scopes in small peer info document (#SPO-276)

      <Icon icon="bin-recycle" iconType="solid" horizontal /> **Removed**:

      * The static path option has been removed from TransportConfig. Please use attachments to serve content instead (#TRAN-256)
      * Deprecated fields in presence have been removed across all SDKs (`queryOverlapGroup`, `meshRole`, `approximateDistanceInMeters`, `rssi`) (#TRAN-680)
    </Accordion>
  </AccordionGroup>
</Update>