Merge pull request #10544 from atennapel/run/4935-UseOldExceptionBehavior-runtime-setting

[RUN-4935] Add documentation for the UseOldExceptionBehavior runtime setting

Author: MarkvanMents

content/en/docs/refguide/runtime/custom-settings/_index.md

@@ -85,6 +85,7 @@ The following custom settings can be configured:
 | <a id="UploadedFilesPath" href="#UploadedFilesPath">UploadedFilesPath</a> | The location of the uploaded files. A valid path can be: `\\FileServer\CustomerPortalFiles`. | [deployment folder]\data\files |
 | <a id="EnableFileDocumentCaching" href="#EnableFileDocumentCaching">EnableFileDocumentCaching</a> | Defines whether file documents should be cached. Only enable this if you are sure that the file documents will not contain sensitive information. Images are always cached. | false |
 | <a id="mapping.import.MaxJsonReadingLength" href="#mapping.import.MaxJsonReadingLength">mapping.import.MaxJsonReadingLength</a> | The maximum length of the JSON string received from the remote which can be processed with import mapping. Use this setting when you expect a string which is longer than the default. See [Import Mappings](/refguide/import-mappings/#troubleshooting) for more information. | 20000000 *(dependent on library version)* |
+| <a id="UseOldExceptionBehavior" href="#UseOldExceptionBehavior">UseOldExceptionBehavior</a> | Allows you to set the exception message and wrapping behavior in the Mendix Runtime Server to the behavior below Mendix version 11.6.0. From Mendix 11.6.0 we changed the way messages are constructed to prevent the actual cause of the error being hidden in the details and exception wrapping is reduced significantly.<br/><br/>This change means that error messages will be different and have a significantly less deep exception nesting. Consequently, code which depends on finding some specific exception hardcoded at X levels deep (using `exception.getCause().getCause()` for example), will probably fail.<br/><br/>To restore the previous behavior, set `UseOldExceptionBehavior` to `true`. | false *Introduced in Mendix 11.6.0.* |
 
 ### ApplicationRootUrl {#applicationrooturl-section}