
Please the following steps:
1.Click Site Actions >> Site Content >> click Form Library in the Document Libraries Section >> click "Open with Windows Explorer" option
2.On the file system, click Organize tab >> click "Folder and Search" Options >> under Hidden files and folder option , select "Show hidden files and folders" radio button
3.Open the 2007 InfoPath template (XSN file) with InfoPath Designer 2013 >> click File >> Info >> Form Options
4.On the Form Options page >> select Compatibility tab, change Form type from Web Browser Form (InfoPath 2007) to Web Browser Form
5.Click Data Connections in the Data Ribbon >> select every Data Connection and click Convert to Current Version button
6.Click File >> Publish >> SharePoint Server
7.On the Publishing Wizard, check the "Enable this form to be filled out by using a browser" box and select "Form Library" option
8.Go to Library settings >> click Relink documents to this library
Please refer to this article Migrating InfoPath 2007 Form to 2013 Forms.
Thanks,
Echo Du
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