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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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