Last update: Download PDF Edit


Release date: July 31st, 2018



  • We fixed the issues in the latest Edge where some of the widgets on the page were not properly destroyed when navigating. (Tickets 64692, 64778, 64918, 64938, 65700)


Release date: December 1st, 2017



  • We fixed the converting issue from Mx4 to Mx5. (Ticket 57663)
  • When deleting a user role, other roles no longer lose information about the roles they can manage. (Tickets 43623, 54117)


Release date: June 19th, 2017



  • When executing a database query results in a connection failure, the system will no longer leak a connection that causes (in the worst case scenario) all the connections to be in-use. (Ticket 48767)
  • We hardened the file upload handler. (Ticket 51685)


Release date: May 24th, 2017


Moving from Mendix 5 to Mendix 6

Please note that after upgrading to Mendix 5.21.7, it will not be possible to upgrade to Mendix 6.10.7, which is currently the latest version of Mendix 6. To migrate a 5.21.7 project to Mendix 6, you will have to wait for the next Mendix 6 release, which is due in a few weeks.


  • Asynchronous running actions are no longer listed as running actions when finished. (Fix 49556)


Release date: February 17th, 2017



  • We made changes to Mendix Runtime to prevent it from blacklisting Refresh in Client events. This prevents Mendix Runtime from getting into a mode in which those instructions are no longer sent to the client. In addition, we ensured that the amount of events going through the system is reduced by ignoring the Refresh in Client instruction, in case the microflows are being run using a system context (which applies to, for example, scheduled events). Also, a warning is logged when the amount of feedback instructions (of which the Refresh in Client instructions are a subset) reaches a certain threshold (5000 items), because such an amount would render the client useless. (Tickets 47984, 48211, 48264, 48564, 49054, 48802)
  • Mendix Runtime will no longer start in acceptance/production mode when an admin user has a password of “1”.


Release date: July 22nd, 2016


New feature

Make it possible to use widgets that are marked as offline capable. Note that actually building offline applications is a Mendix 6 feature.


  • Administration ‘about’ action now includes Java version.
  • Amazon aws-sdk-java is updated to 1.10.69 version. This version includes the fix for incorrect formatting of date headers in case of Java 1.8u60 and later, causing the server rejecting the requests. See the AWS Github issue page for more information.
  • Due to a number of reasons orphan files can exist in the local filesystem of an app. Orphan files are files in the uploaded file directory which do not have a corresponding database entry. As not all causes of files becoming orphan files can be resolved a scheduled clean-up is introduced in this release to do clean orphan files automatically. In this release this scheduled task is turned off by default, so that this will for now only run for applications which explicitly turn this on. To do this set the custom setting ‘com.mendix.core.localfilesystem.cleaning.isEnabled’ to ‘true’. See for more details here. When clean-up goes well for all apps which test this procedure, the scheduled task will be turned on by default in a next release. (Tickets 263923, 419169, 463045, 463881, 464147, 464233, 464504)


  • When “Send binary data as attachments (MTOM)” is disabled in the consumed web service document, the “xml:” namespace is no longer added to the SOAP body message because it is not allowed to be present by Microsoft web services. (Ticket 466164)
  • Fix confirmation dialogues so that they are blocking again. (Ticket 464792, 463453)
  • Memory usage reporting in monitoring (‘runtime_statistics’) for Java 8. Java 7 fields “survivor”, “tenured”, “code”, “permanent” and “eden” elements are deprecated and instead use “memorypools”. Old memory fields have a value of 0 for backwards compatibility reasons. For more information see the “memory” section in the Monitoring documentation. (Ticket 465551)
  • Fixed ‘Remove’ list operation for the case where the object to be removed was retrieved in a different manner (e.g. ‘by association’ instead of ‘from database’) than the object in the list, which lead to in-equal objects. (Ticket 464178 and 466689)
  • Updated BouncyCastle libraries to the newest signed versions. This makes sure a signed provider is used and fixes the ‘JCE cannot authenticate the provider BC’ error. (Ticket 466314)
  • Fixed an issue when Edm.Decimal representation in XML for OData had a scientific notation. (Ticket 466590)
  • Fix memory leak when generating documents. (Ticket 465251)

Known issue

  • Opening the AppStore in the Mendix Modeler fails for Windows 10 in some cases. This is due to the %USERPROFILE%\AppData\Local\Microsoft\Windows\INetCache directory being read-only. A workaround is to follow these steps: 1. Open the %USERPROFILE%\AppData\Local\Microsoft\Windows\INetCache directory 2. Right-click -> Properties 3. Uncheck the ‘Read only’ attribute


Release date: April 20th, 2016



  • Fixed issue when MTOM attachment reference in XML had xmime:contentType attribute even if it was not provided by export mapping (Ticket 374374, 463341, 464052, 465254)
  • Attribute namespaces in XML messages did not apply prefixes correctly (Ticket 447172, 463535)
  • Fix flickering of the page when navigating to a page in content.
  • Fix login issue when named user limit is reached, causing all users to be locked out of the application. Users with the System.Administrator role can now always log in, even when the number of users has exceeded the number specified in the license. Previously only the user with the Administrator name, MxAdmin by default, could log in. This user is not available on sandboxes however. (Ticket 465382)


Release date: March 23rd, 2016



  • Fixed query string encoding for the next page url in OData response (Ticket 464950)
  • Fixed conditional visibility check in the Modeler that could cause the security check to fail (Ticket 464763)

Known Issues

  • Filedocument storage on S3 is not compatible with Java JDK 1.8.0 u60 and up. (Ticket 39389)


Release date: February 22nd, 2016



  • Fixed issues related to conversion from Mendix 4. (Tickets 463586, 462850)
  • Fixed issues related to conversion of excluded Domain-to-XML and XML-to-Domain mappings. (Tickets 416284, 387305, 463573)
  • Fixed issue where an XSD reference in a WSDL section was not deployed correctly. (Ticket 463626)
  • Fixed device type in client for large session data responses (e.g. when there are a lot of entities in the domain model that are visible to the user). (Ticket 464004, 463916)
  • Fixed incorrect value of ‘$currentDevicetype’ in the homepage microflow. (Tickets 463112, 463916)
  • Fixed storage of non-localized date attributes as localized values. (Ticket 463941)
  • Fixed clicks on the date picker being ignored on Windows Phone. (Ticket 463945)
  • Fixed an issue where conditionally visible widgets could cause flickering of the page, a changing scroll position, or the scrollbar sometimes not appearing. (Ticket 463592)
  • Fixed memory leak in the data view which caused a noticeable slowdown and could even crash the browser. (Ticket 464612)
  • Fixed an issue in setting a custom configuration value for ‘UploadedFilesPath’. Because of a race condition, the custom value was sometimes not picked up by the module which handles uploads to the local filesystem. (Tickets 463877, 464498)
  • Fixed nullpointer exception when ‘ClientQueryTimeout’ is set and a user has no rights to execute a query.

NOTE : It is recommended to convert your existing Mendix projects directly into the 5.21.2 version of the modeler to incorporate above mentioned fixes.


Release date: December 10th, 2015



  • Added menu item Tools > Batch Update Layouts to quickly change the layouts of many pages. This is especially useful for pages that are still pointing to a layout that has the property ‘Use main placeholder for pop-ups’ set to ‘Yes’. You can limit the pages to update based on the way they are opened, e.g. only update pages that are always opened in content. See also https://www.mendix.com/blog/batch-updating-page-layouts/
  • Notify the user if the cache bust is not configured in index file of the theme. (Ticket 370276)


  • Fix data views doing a full refresh while only the rendering should be updated. (Ticket 463051)
  • Fix the flickering of the sidebar transition during navigation to another page. (Ticket 304502)
  • Disallow multiple home pages for the same user role.
  • Fixed exceptions and incorrectly constructed queries around entities where the depth level of the specializations is more than two. (Ticket 463510)


Release date: October 28th, 2015


Page templates are now out of beta!

Backwards compatibility breaking changes

  • Having virtual attributes specified in an OQL select clause or in a retrieval schema will cause an exception, because that kind of attributes will be handled as non existing attributes. Previously, only an error was logged and the attribute was skipped.

New features

  • The new and shiny radio buttons widget can be used to show enumeration and boolean attributes. When generating a page or when dragging a boolean attribute from the connector to a page, the Modeler will now generate radio buttons instead of a check box. For enumerations with less than six values, the Modeler will also generate radio buttons, otherwise a drop down will be inserted. Radio buttons will not be generated if page templates are disabled.
  • Mendix objects can be stored in the session by associating them to System.Session. See custom session data.


  • Every security check error is now reported separately, instead of reporting only the first one.
  • The stand-alone “New” button is hidden if you do not have create rights or access to the page.
  • Upgraded Bootstrap from 3.3.2 to 3.3.4.

Changed Behavior

  • When persistent sessions are enabled, the ‘LastActive’ value is committed to the database only once every ClusterManagerInterval (default: 5 minutes), instead of every request. This drastically improves performance when using persistent sessions. See here for more information.
  • User actions now need to be registered before they are referenced in Before, After or Replace events of the ActionListener API. Doing the registration too late will result in a warning, not doing it at all results in undesired behavior of the Mendix Business Server (exceptions).


  • Fixed an issue in the Modeler where opening a project from a UNC path (\\server\share\...) was not possible anymore. This especially affected users who run the Modeler in Parallels on Mac, as Parallels exposes the shared documents folder as a UNC path in Windows by default. (Tickets 356950, 448574)
  • Resolved a crash in the Modeler that could occur when converting a Mendix 4.x project.
  • Added project setting “Enable widget bundling” to always bundle custom widgets when deploying. (Ticket 384320)
  • Order of client refresh responses is now guaranteed, to ease parsing of client traffic (Ticket 416509)
  • Enabled download buttons if there is a file to download even if the surrounding data view is disabled. (Ticket 313170)
  • Clicking on a list view item nested in another list view item will no longer trigger the action of the parent item. (Ticket 102835)
  • Search fields for dates on grids now respect the custom date formats specified in the language options. (Ticket 101024)
  • Fixed concurrency issue which in rare cases (heavy load and advanced security constraints) could cause a runtime to keep on running at 100% CPU and become unresponsive (Ticket 447237).
  • Fixed an issue in the Mendix Business Server where the output value of a microflow could still be processed, despite the return type being ‘Nothing’. Now all return values of return type Nothing will be ignored as expected. (Ticket 397625)
  • Fixed ActionListener API to accept both Action Names as Class Names as valid input for the Before, After and Replace events (Tickets 100510 & 21646).
  • Removed confusing log warning which could occur when an object could not be retrieved (“Object with id ‘%ID%’ could not be retrieved.”) (Ticket 262163).
  • Fixed list views using a microflow data source. (Ticket 462867)


  • If you upgrade your database from a pre-Mendix 5.21 model, the default values of date and float attributes will cause a change in the system tables of Mendix. This has no effects on any user data but is only necessary for the database synchronization handling.

Known issues

  • Queries involving entities with more than 3 levels of inheritance may be constructed incorrectly.

Deprecated features

  • MxObjectCache, available through LocalComponent, has been deprecated. MxObjectCache is an internal construct, as such it is not part of our public API, consider using custom session data instead.
  • ISession.getData(), ISession.retain(), ISession.release(): These methods have been deprecated, use an association to System.Session to store objects in a session instead. Consider using custom session data instead.