First of all, you need to add a new dependency for the Web Module of your application with a new version of the jQuery library, for example:
Then you need to specify a new path to the jQuery library which is used in a project as WebJar. To do so, define the
cuba.web.webjars.jqueryPath property in the
web-app.properties file, for example:
cuba.web.webjars.jqueryPath = jquery/3.2.1/jquery.min.js
Pay attention that the FileUploadField uses the jQuery UI and jQuery FileUpload libraries, so make sure that a new version of jQuery is compatible with them.