.NET Agent Release Notes

2026
2025
2024

2026-11-02

v2.5.7

Fixed Fixed an issue where host resource metrics were not collected until the agent restarted after the OS returned an abnormal cumulative CPU value.

2026-08-03

v2.5.6

Fixed Fixed a bug where the return value store instruction was skipped at return points shared by multiple branches during IL rewriting, generating invalid IL.

2026-07-10

v2.5.5

New Added SqlDataAdapter.Fill instrumentation

New Added SqlDataAdapter.Update instrumentation

Records the count as the actual number of affected rows (RecordsAffected), without duplicating the existing ExecuteNonQuery hook.

Changed Changed the log file name from {date}-{PID}.log to {date}-{GUID}.log

Fixed Improved native profiler stability

Fixed Improved logging logic stability

2026-06-09

v2.5.4

Feature Added HTTP response status code collection

Exposes response codes (2xx-5xx) for all transactions.

2026-04-21

v2.5.3

New Added trace_user_using_ip Boolean option

Default value: true
When set to false, enables cookie-based user tracking

Fixed IIS AppPoolIdentity Global Mutex permission error

Grants FullControl to Everyone via MutexSecurity, allowing Global Mutex creation and acquisition from low-privilege processes

2026-02-24

v2.5.2

New Linux OS support

Ubuntu 20.04 and later

Feature Added Commit, Rollback tracking in DB Step

Fixed Fixed load failure caused by assembly redirection for assemblies not provided by .NET Framework

2026-01-26

v2.5.1

Fixed Updated to collect non-standard ports as well during domain data collection

2026-01-13

v2.5.0

New Support for .NET Core 9.0

Feature Added support for MongoDB (MongoDB.Driver.Core) monitoring

Feature Added module dependency inspection feature

Feature Web framework support

WCF
WebService
Web API

Changed Refactoring of the internal agent architecture to improve stability and scalability

Fixed Fixed an issue where a memory leak occurred during AppDomain reload

2025-07-22

v2.4.4

Fixed Fixed an issue where transactions were marked as Lost Connection even though they had completed normally during circular calls.

2025-06-25

v2.4.3

New Added the app_context_stat category to matrix metrics

app_context_enabled Boolean
- Default: false
- When set to true, enables the full app_context_stat data collection feature
app_context_parser
- Use one of: default, prefix, match
- default: Default parser (extracts the first path segment)
- prefix: Prefix-matching parser (most flexible)
- match: Exact-matching parser (only matches fully identical paths)
app_context_parser_reset Number
- Default: 0
- A counter that forcibly resets the parser’s internal cache and configuration
app_context_path_depth Number
- Default: 1
- Specifies the depth of path segments to extract from the URL (used only with the default parser)
app_context_path_set String
- Defines a mapping of paths to monitor and their display names. Use a comma (,) to separate multiple entries
- Example: name1@url1,name2@url2,url3,name4@url4

New Added an option to display the original URL in step traces when URL normalization is applied

step_origin_url_enabled Boolean
- Default: false
- When URL normalization is applied, the original URL is also displayed in step traces.

Fixed Fixed an issue where the original URL was not displayed in record summaries when URL normalization was applied.

2025-04-26

v2.4.2

New Modified to automatically select a version based on the .NET runtime version of the installed server.

2025-03-21

v2.4.1

New Added the ISAPI filter-based transaction tracing feature.

2025-03-04

v2.4.0

New Supported transaction monitoring for WCF, ASP, CGI, ISAPI, and such by using the ISAPI filter.

Fixed Fixed the issue where X-Forwarded-For is not applied in WebForm.

2025-01-23

v2.3.9

Changed Improved backward compatibility with .NET framework 4.5 or earlier.

Changed Improved the method hook process.

2025-01-20

v2.3.7

New Added support of the MySQL driver to .NET Core.

It supports MySQL drivers through ADO.NET as well as direct MySQL data providers such as MySQL Connector/Net.

Fixed Fixed the error where the client IP address appears as 0.0.0.0 in .NET Core.

2025-01-15

v2.3.8

New Supported LIthe NQ to SQL (System.Data.Linq) monitoring.

New Added the agent option to set the section name to exclude from monitoring.

2024-11-25

v2.3.6

New Added the agent options.

webservice_method_prefix_realtime Boolean

Changed Changed the processing method for the transactions collected through the webservice_method_prefix option.

Modified to ignore the webservice_method_prefix methods collected within transactions to prevent errors caused by recursive calls.
Modified to ignore unfinished transactions.

Changed Merged installers for .NET Framework and .NET Core environments provided for separate downloads.

2024-11-04

v2.3.5

New Added the User Transaction feature in .NET Core.

See the following example: If you do not need to monitor the number of users, enter an empty string in the user identification field.

using System;

class Program
{
    static void Main(string[] args)
    {
        // Start tracing (domain, Url, user identification)
        WhatapDiagnostic.TraceStart("127.0.0.1", "/api/test", "user123");

        try
        {
            // Start step
            WhatapDiagnostic.StepStart("test Step");

            // User code area

            // End step
            WhatapDiagnostic.StepStop();
        }
        catch (Exception ex)
        {
            // Log exceptions in diagnostic information upon an exception
            WhatapDiagnostic.SetExceptionForTrace(ex);
        }
        finally
        {
            // End tracing
            WhatapDiagnostic.TraceStop();
        }
    }
}

Note

Supporting the .NET Framework is in preparation.

The WhatapDiagnostic code is as follows. The format does not matter, as long as the content of diagnosticSource.Write(…) is correct.

using System.Diagnostics;å

public static class WhatapDiagnostic
{
    private static readonly DiagnosticSource diagnosticSource = new DiagnosticListener("WhatapDiagnosticListener");

    public static void TraceStart(string host, string url, string userId)
    {
        if (diagnosticSource.IsEnabled("Whatap.Diagnostic.Trace.Start"))
        {
            diagnosticSource.Write("Whatap.Diagnostic.Trace.Start", new { Host = host, Url = url, UserId = userId });
            Console.WriteLine("Whatap.Diagnostic.Trace.Start!");
        }
    }

    public static void SetExceptionForTrace(Exception exception)
    {
        if (diagnosticSource.IsEnabled("Whatap.Diagnostic.Trace.Exception"))
        {
            diagnosticSource.Write("Whatap.Diagnostic.Trace.Exception", exception);
        }
    }

    public static void StepStart(string message)
    {
        diagnosticSource.Write("Whatap.Diagnostic.Step.Start", message);
    }

    public static void StepStop()
    {
        diagnosticSource.Write("Whatap.Diagnostic.Step.Stop", new { });
    }

    public static void TraceStop()
    {
        if (diagnosticSource.IsEnabled("Whatap.Diagnostic.Trace.Stop"))
        {
            diagnosticSource.Write("Whatap.Diagnostic.Trace.Stop", new { });
        }
    }

    public static void UserLog(string message)
    {
        if (diagnosticSource.IsEnabled("Whatap.Diagnostic.UserLog"))
        {
            diagnosticSource.Write("Whatap.Diagnostic.UserLog", message);
        }
    }
}

New Supported the Method hook.

You can monitor by specifying the method name. See the following configuration.
```
hook_methods_enabled=true
hook_methods_prefix=System.Net.Http.HttpClient., System.Net.WebRequest., System.Data., System.Net.Http.
hook_methods_ignores=get,set
```
- Set the value of the hook_methods_enabled option to true.
- The value of the hook_methods_prefix option becomes the monitoring target when the first part of the option value matches. Separate with comma (,).
- The value of the hook_methods_ignore option is excluded from monitoring when the first part of the value matches.

New Added the feature to support the WebClient.DownloadString method monitoring.

Changed Processed the response body option.

Added the enabling option instead of the default setting because the string encoding-related error was found.
The default value of the profile_http_response_body_enabled option is false.

Changed Changed the Redis output format for the .NET Framework version.

The decoration effect has been applied to match the output method of .Net Core.

Deprecate Removed the trace_db_command_methods option.

This option is currently not required due to automatic processing of monitoring targets.
The methods excluded from monitoring can be processed using the Method hook.
```
hook_methods_enabled=true
hook_methods_prefix=System.Data., ...
```

2024-10-02

v2.3.4

Fixed Temporarily removed the CancellationToken-related methods from recently added monitoring targets.

New Added support for setting the expand_transaction_level in .NET Core.

expand_transaction_level Boolean

Default false

If you set this option to true, SQL and HTTP calls that occur outside transactions are considered transactions and they are displayed in the hitmap.
expand_transaction_basetime Int

Default 1000 ms (1 second)

When the expand_transaction_level option is set to true, data is collected only for requests that take longer to respond than the specified time. It collects up to 100 items per second. The minimum value is 100 ms (0.1 second).

New Added support for desktop application monitoring.

Set the value of the expand_transaction_level option to true.

Before running the application, enter the following command at the prompt:

SET COR_PROFILER={D76F1D76-A9E0-4C87-874F-C0AD93D4229B}
SET COR_ENABLE_PROFILING=1

SET CORECLR_PROFILER={21CAE18A-4E44-4578-83FD-0576AAA47E68}
SET CORECLR_ENABLE_PROFILING=1
SET DOTNET_STARTUP_HOOKS=C:\Program Files\WhaTap .NET\core\Whatap.Startup.NetCore.dll

SET WHATAP_TRACE_IIS_ONLY=0
SET EXPAND_TRANSACTION_LEVEL=1
SET EXPAND_TRANSACTION_BASETIME=100

After executing the command, run the target application.

2024-09-25

v2.3.3

New Added support for SQL parameter monitoring in .NET Core.

New Added support for Stored Procedure monitoring in .NET Core.

New Supported the System.Net.Http.HttpClient.SendAsync monitoring.

Fixed Fixed the bug where active stacks are not collected when additionally installing the .NET framework version without uninstalling the .NET Core version of the agent.

2024-09-05

v2.3.2

New Added the agent option to set suffix of URLs to exclude from transaction collection.

trace_ignore_url_suffix String

Fixed Added the parameterized query tracing feature.

Fixed Fixed the error occurring in the status code display of REST API transactions.

Fixed Added the methods related to System.Data.Common.DbCommand that are not included in monitoring.

Added some missing overloaded methods among the following asynchronous methods.

2024-08-26

v2.3.1

New Added the feature to collect traces that occur outside of transactions.

expand_transaction_level Boolean

Default false

If the option value is set to true, SQL and HTTP calls that occur outside of transactions are treated as transactions and displayed in the hitmap.
expand_transaction_basetime Int

Default 1000(1 second) / Min 100(0.1 second)

When the expand_transaction_level option is true, data is collected only when the response time is longer than the set time. It collects up to 100 cases per second.

New Display DB connection information: Added the feature to display database connection information for transactions using the database.

Changed Modified to display the status code of a transaction even if it is not an error.

2024-07-31

v2.3.0

Fixed Fixed the error where SQL and HTTP monitoring are missing in v2.2.9.

Fixed Improved the issue where UDP packets are corrupted when packet processing is delayed.

2024-07-05

v2.2.9

Feature Supporting multi-transaction monitoring: You can trace calls between the application services registered as projects on the WhaTap monitoring platform.

2024-06-19

v2.2.8

New Additionally supported .NET 6, 7, and 8.

Supported the ASP.NET core.
Supported the HTTP call, Redis, WCF client, user log, Active Stack, and SQL.
Download it by using a separate installation link. whatap_dotnet_core.exe

Changed Changed the default value of the trace_http_client_ip_header_key option to X-Forwarded-For.

2024-06-10

v2.2.7

Changed Improved the support environment analysis tool (WhaTapDotnetScan.exe).

Improved so that it can run even in environments where .NET has not been installed.
Fixed the error that occurs when using a lower version of the .NET runtime or when the .NET runtime has not been installed.

Fixed Fixed the bug where the end point is deleted, leaving only the start point during removal of transactions that exceeded the processing allowance.

2024-05-24

v2.2.6

Feature Added the agent options

trace_ignore_url_set String

Set URLs to exclude from transaction tracing. To set multiple values, use comma (,) as the delimiter.
trace_ignore_url_prefix String

Set the transaction collection exception URL's prefix. Any URLs whose prefix matches the set value do not collect the transaction performance. To set multiple values, use comma (,) as the delimiter.

Changed Modified to select the agent configuration's option to set whether to monitor System.Data.Common.DbCommand.

Some customers found that errors occurred due to outdated assemblies. Because we could not find a perfect cause to reproduce the error, it was excluded from monitoring.
To add it as the monitoring target, set the following agent option and restart IIS.
Tip
trace_db_command_methods String
Enter the name of the method to monitor. To set multiple values, use comma (,) as the delimiter. To monitor all methods, apply as follows:
whatap.conf
trace_db_command_methods=ExecuteReader, ExecuteReaderAsync, ExecuteNonQuery, ExecuteNonQueryAsync, ExecuteScalar, ExecuteScalarAsync

2024-05-08

v2.2.5

Fixed Fixed the error that accelerates bottlenecks because monitoring messages have been delayed and piled up when the server's CPU performance is limited.

2024-04-30

v2.2.4

Feature Improved the bytecode processing performance.

Feature Improved the log processing performance.

Feature Improved the UDP packet processing performance.

Feature Improved the ASP.NET MVC library processing performance.

2024-04-24

v2.2.3

Fixed Fixed the bug where the CPU usage increases under specific conditions during Rest API monitoring.

The bug was fixed because the CPU usage increased for specific customers.
Even for the customers with no symptom, it is recommended to upgrade the agent. It helps improve performance.

2024-04-18

v2.2.2

New Added the DataAdapter.Fill() method monitoring.

New Supported WebForm monitoring and handled page movement events as transactions.

Feature Added the agent option, trace_http_client_ip_header_key. For more information, see the following.

Fixed Fixed the issue where concurrent users are not displayed properly due to the IP address display error.

Deprecated Stopped support of the profile_http_body_enabled option due to potential crash while the agent is reading the body.

2024-04-09

v2.2.1

Feature Added the agent options

prepend_app_pool_name Boolean

Default false

If the option value is set to true, the full name of the application appears before the URL of the transaction.

Changed Separated installation files to increase compatibility with older versions.

In case of using the runtime at .NET 4.6.1 or later: whatap_dotnet.exe
In case of using the runtime at earlier than .NET 4.6.1 or later, or in the environment earlier than Windows Server 2012: whatap_dotnet.exe

Note
It is available starting from Windows Server 2008.

Fixed webservice_method_enabled option: Fixed the bug where the methods are not monitored when executed nested.

Fixed Fixed the issue where the whatap.conf file is not found in the 32-bit .NET runtime.