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If you see this error message, when using a flow, the Element Name field on the Flow Properties Panel is most likely empty. You must edit your form/flow, explicitly set the flow 'Element name' in the properties panel back to the default value 'form' or to the value that was set to before. This value must match what is in your database or loading the flow from an old submission will not work. The error in the image occurred when the manager tried to access a task from the Task List in a flow with an empty element name field:

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If you have been using the name attribute in v4 forms, it will not be available when creating v5 forms post-migration. Code which uses the submission xml in your integrations will need to be modified to use the root element name instead of the name attribute in the root element.

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There are new strings present in the default locale properties file for forms/flows in v5. For example.: strings for mobile devices. You will need to manually add these new strings to your uploaded locale files for forms created in v4. New strings can be found by downloading the v5 default properties file for your form. Server wide customizations can be done by unzipping the <frevvo-home>/tomcat/webapps/frevvo.war. See this documentation for the details.

Data API

The browser doc feature in  v4 is no longer supported. It introduced a new doc action that can be enabled by the API and where, on submission, the XML document would be sent back to the browser with the HTTP response. This enabled the capture of updated XML and make sure it updated their own systems in a single db transaction.

 In 5.x, we have a new mechanism. It is possible now to submit forms using the API and receive back a DataSource? with multiple parts (multipart/form-data) one for each submission document: XML, snapshot, attachments, etc. This is above and beyond what the browser docs provide, but much simpler. See API's submitInstance() and Data Source documentation (coming soon...). 

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