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FIX Client Simulator Release Notes

FIX Client Simulator Release Notes

Jan 23, 2026

FIX Client Simulator 3.13.0

FIX Client Simulator 3.13.0 was released on 21.01.2026

New Features and Improvements

The FIX Client Simulator 3.13.0 release introduces a configurable Grid View for the events. Previously, INFO and FIX messages were displayed as plain text in a List View, which made long event streams hard to read.

A new configurable Grid View provides a structured, table-like layout. It also allows you to configure the view by right-clicking on the columns, including highlighting specific FIX tags for easier navigation and readability. To switch between List View and Grid View, we added a checkbox at the bottom (Grid View) that lets you toggle between the two views.

FIX Client Simulator 3.12.0

FIX Client Simulator 3.12.0 was released on 02.07.2025

Fixed Bugs

  • Fixed issue with invalid FIX message, now all the errors are shown in the Events Viewer

FIX Client Simulator 3.11.0

FIX Client Simulator 3.11.0 was released on 05.02.2025

New Feature

The FIX Client Simulator 3.11 release introduces Kafka session integration, supporting existing features - the Send Message Tab, Auto-increment and Replay Logs - to work seamlessly with Kafka.

 

The FCS Kafka session supports the following functionality:

  • Producer & Consumer Creation

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    • Configure topics, groups, optional keys, and more.

  • Authentication & SSL/TLS

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    • Supports SASL/Plain (username/password) or no authentication.

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    • Optional SSL/TLS encryption with the ability to validate certificates.

  •  

    • User can send or receive a FIX message or arbitrary text (non-FIX content) via Kafka sessions.

  •  

    • FIX-specific features (like the context-driven workflows, validation, and auto-increment) are supported but require proper FIX tag=value formatting.

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    • Automatically increment fields (e.g., sequence numbers) in FIX messages, just like in FIX sessions.

  •  

    • Replay FIX message logs using Kafka session, facilitating troubleshooting, performance review, and re-testing.

FIX Client Simulator 3.10.0

FIX Client Simulator 3.10.0 was released on 24.09.2024

New Features and Improvements

 

The FIX Client Simulator 3.10.0 release introduces the "Backup Connection Parameters" section, which allows configuring a backup connection to ensure a seamless transition if the primary connection fails.

  • "Enable Cyclic Switch Backup Connection" will cyclically try to reconnect to the primary and backup if either is lost

  • "Enable Auto Switch to Backup Connection" automatically switches to the backup if the primary fails after a few attempts. If disabled, no backup attempt will be made

  • "Keep Connection State" retains the same log files for both connections if enabled. If disabled, separate logs will be created for the backup connection

In the FIX Client Simulator 3.10.0 release, the Message Details window has been enhanced with the following features:

  • Added a tag search functionality, allowing users to find tags by number through the auto-search bar located at the top of the window.

  • Implemented the ability to add and remove tags directly within the interface.

  • Tag information (number, name, value) is now displayed in a simplified and organized format, accompanied by actionable icons.

FIX Client Simulator 3.9.0

FIX Client Simulator 3.9.0 was released on 24.06.2024

New Features and Improvements

 

The FIX Client Simulator 3.9.0 release introduces a multiline session display option within the Session list. Previously, session details were confined to a single row, causing readability issues. This update allows to enable "Multiline Session Display" through the Options menu. This functionality allows users to have control over how they view session information.

With FIX Client Simulator 3.9.0 release it is possible to access detailed message information within the Event Viewer. By right-clicking on a specific message and selecting "View FIX Message" a dedicated window launches, presenting comprehensive message data in a structured table format. This window offers the functionality to collapse and expand sections containing repeating groups, allowing users to efficiently navigate and analyze message content.

FCS Console now offers the ability to replay log files and the "Help" command has been expended for detailed guidance. The available options for log replay customization are the following and they allow to:

  • Log File: Specify the precise log file to be used for the replay.

  • Repeats: Define the number of times you want to replay the chosen log file.

  • Speed Multiplier: Adjust the replay speed to run faster or slower than the original session.

  • Message/Second: Control the message rate during replay based on timestamps within the log file.

  • Sequence Numbers: Choose which sequence numbers to process or exclude from the replay.

  • Message Filtering: Select specific message types to include or exclude from the replay process.

  • Session Timeout: Set the maximum wait time for establishing the replay session to avoid unnecessary delays.

FIX Client Simulator 3.8.0

FIX Client Simulator 3.8.0 has been released on Feb 8, 2024 

New Features and Improvements

 

FIX Client Simulator now provides the ability to select incoming Order Single (35=D) message in the Events Viewer section and automatically form the Execution Report (35=8) with 39=8 to send in running Initiator or Acceptor session (reject).

When working on test scenarios at the stages “Expect”, “Expect Until”, and “ExpectThenSend”, the tags that go into specific repeating groups can already be validated, not just based on a particular tag but also with an asterisk (*) instead of 0,1,2, etc.

FIX Client Simulator now has Balance quantities checkbox which allows checking the messages     “Partial Fill” and “Fill”, balance 32, 14, 151 tags by filling empty values with correct values according to the order flow when "Balance order quantities" is set and incoming message is New Order Single.

If Partly Fill, and Fill do not contain some of tags 32, 14, 151, the tags will be added.

If the user sets some of the tags to have an incorrect value (too big or too small), the tags will be filled in with correct values.

Additionally, tag 6 (AvgPx) is being calculated.

FIX Client Simulator now has been updated with button “duplicate command” as well as other commands have been changed to icons instead of wording.

Coloring on the active test scenario button has been added to make it easier to define the running scenario among others as well as the name of the running session is being displayed under “Session” column.

With 3.8.0 release it is already possible to manually configure the delays between messages in ExpectThenSend command Parameter. Additionally, the random delay interval can be set up with minimum and maximum values as well as fractional values are possible for seconds.

Now the horizontal scroll bar will be displayed in Event viewer only when it’s needed.

Fixed Bugs

  • Fixed issue with test execution time being displayed incorrectly if it is higher than 1h

  • Fixed issue with error message not being shown when user trying to run Test Scenario after scenario file being deleted

FIX Client Simulator 3.7.0

FIX Client Simulator 3.7.0 has been released on Dec 7, 2023.

New Features and Improvements

Fixed Bugs

  • Fixed the issue when FIX Client Simulator could not be closed correctly when 1M messages were sent.

  • Fixed the issue when FIX Client Simulator didn't check the user's RO permissions to replay log files on Linux.

FIX Client Simulator 3.6.0

FIX Client Simulator 3.6.0 is released on Nov 3, 2023.

New Features and Improvements

Fixed Bugs

  • Fixed the issue when the outgoing Heartbeat(35=0) message was displayed twice in the Events Viewer section.

  • Fixed the issue when the Reject(35=3) message wasn't displayed in the Events Viewer section when the unexpected Resent Request message(35=2) was received.

  • Fixed the issue when FIX Client Simulator allowed the creation of multiple FIX sessions with identical names.

  • Fixed the issue when the values of the Rate and Send count fields could not be set to defaults.

  • Fixed the issue when the Allow message resending flag was not functioning correctly.

  • Fixed the issue when FIX Client Simulator continued sending messages to the deleted FIX session.

FIX Client Simulator 3.5.0

FIX Client Simulator 3.5.0 is released on Sep 15, 2023.

Package Improvements

FIX Client Simulator 3.4.0

FIX Client Simulator 3.4.0 is released on Aug 2, 2023.

New Features and Improvements

FIX Client Simulator 3.3.0

FIX Client Simulator 3.3.0 is released on Jul 4, 2023.

New Features and Improvements

Fixed Bugs

  • Fixed the issue when the Autoincrement tags functionality worked incorrectly when the autoincremented tag was inside of the repeating group.

  • Fixed the issue when FIX Client Simulator could not send a custom Logon message if the AdditionalParsersList property was specified with the 'ADD@FIXT11:FIX44' value.

FIX Client Simulator 3.2.0

FIX Client Simulator 3.2.0 is released on May 29, 2023.

New Features and Improvements

FIX Client Simulator 3.1.0

FIX Client Simulator 3.1.0 is released on Apr 12, 2023.

New Features and Improvements

  • The ability to replay QuickFIX log files.

  • The ability to set the initial tag value for auto-increment.

  • FIXLatest application version support.

Fixed Bugs

  • Fixed the issue when FIX Client Simulator could not send FIX 5.0 messages when the 1128 tag was not specified.

  • Fixed the issue when FIX Client Simulator displayed a console error when the main application window was resized.

  • Fixed the issue when FIX Client Simulator could not generate new application messages with the FIX50 version.

  • Fixed the issue when the FIX message containing another FIX message was not parsed correctly in the Replay log files functionality.

  • Fixed the issue when FIX Client Simulator incorrectly counted FIX messages when the log file with spaces or empty lines was replayed.

  • Fixed the issue when the splash screen was displayed with delay.

  • Fixed the issue when the message color disappeared in the Events Viewer section after maximizing the application window.

  • Fixed the issue when FIX Client Simulator did not replay log messages if the timestamp was added to the Send Message tab.

  • Fixed the issue when FIX Client Simulator incorrectly identified the beginning of the message in the Send Message tab.

  • Fixed the issue when FIX Client Simulator could not recreate a session using a custom dictionary if the previous session with the same name was non-gracefully terminated.

FIX Client Simulator 3.0.0

FIX Client simulator 3.0.0 is released on Oct 11, 2022.

New features and improvements

Fixed bugs

  • Fixed the issue when some symbols (i.e. №) were sent incorrectly while replaying the log file.

  • Fixed the issue when FIX Client Simulator crashed for FIX sessions with FIX 5.0SP2 version while using the wrong dictionaries.

  • Fixed the issue when some symbols were sent incorrectly if the message was created from the template.

  • Fixed the issue when incoming Resend Request(2) messages were not shown in the FIX Client Simulator.

  • Fixed the issue when a corrupted in/out log file was created for the admin session if the FIX Client Simulator was connected to FIXICC.

FIX Client Simulator 2.30.0

FIX Client Simulator v.2.30.0 is released on Aug 19, 2022 

New Features and Improvements

  • The ability to use pipe delimiter for tags in FIX message in the 'Send Message' tab.

  • The ability to save the FIX message as a file via context or main menu.

  • The ability to load FIX messages in the 'Send Message' tab from the file.

Fixed bugs

  • Fixed the issue when long FIX messages could not be shown in the Events Viewer window.

  • Fixed the issue when FIX Client Simulator displayed an unclear parsing error when the user sent an invalid message.

FIX Client Simulator 2.28.0

New Features and Improvements

Fixed bugs

  • Error sending messages containing internal raw FIX messages from Send Message tab.

FIX Client Simulator 2.27.0

New Features and Improvements

  • Display administrative messages in console

  • Create message from template

  • “Send Message“ functionality extended to work with multiple messages 

  • “Send message“ window visualization was improved with highlighted "tag=" and rich undo/redo functionality

  • Configuration settings file path was simplified

  • Configuration settings file made available for user (to copy/paste/export/share)

  • Previous user configuration settings can be used after upgrading to a new version 

  • Added an ability to send a message(s) without any delays, when the Rate field is set to "0"

  • Improved “Edit message “ interface usability

Fixed bugs

  • Auto-increment logic for the fields of decimal types was fixed

FIX Client Simulator 2.26.0

New Features and Improvements

  • FIX logs replay feature has been implemented

  • An ability to autoincrement tags while sending has been implemented

  • FIX Client Simulator persists the following data between program runs :

    • Position and size of the main window.

    • Names and parameters of all created sessions. Sessions can be restored in a connected or disconnected state. 

    • Edited message.

    • Value for Autoincrement tags edit box.

    • Values of Rate and Send Count controls for both Send Message and Replay tabs.

    • Values for other controls from the Replay tab: Log file, Sequence numbers, Filter, Use timestamps and Speed.

    • Values for checkboxes from the Events Viewer menu and Options menu.

and restores them at the start.

FIX Client Simulator 2.25.1

New Features and Improvements

Fixed bugs

  • The tag number of the repeating group is invisible in the message details window

FIX Client Simulator 2.21.0

New Features and improvements

  • MSVC 2010 Redistributable Package  has been added to the Simple Client package

FIX Client Simulator 2.17.0

Fixed bugs

  • The issue with the usage of TLS v1.0 for the SSL connection has been fixed.

FIX Client Simulator 2.16.0

New Features and Improvements

  • Extended options for the "Reset sequence numbers" checkbox have been added

FIX Client Simulator 2.15.0

New Features and Improvements

  • Visibility of Session-Level Reject (35=3) messages in the Events Viewer section.

  • The ability to send FIX 5.0+ messages even if the ApplVerID(1128) tag is absent.

FIX Client Simulator 2.14.0

New Features and Improvements

  • The SSL security protocol support for FIX sessions.

  • Sending all messages to a single FIX session by default when there is only one connected session.

Fixed Bugs

  • Fixed the issue when the text from the Events Viewer section could not be copied.

  • Fixed the issue when the Batch Send button was unavailable when more than one session was selected.

  • Fixed the issue when UTF-8 encoding worked incorrectly.

FIX Client Simulator 2.13.0

Fixed Bugs

  • Fixed the issue when FIX Client Simulator could not handle Logon response if the ForceSeqNumReset property was set to 'true'.