This is a simplified version of https://www.polymer-project.org/2.0/docs/upgrade. It also lists what warnings and fixes are available for each upgrade task.
<dom-module> using is or name should be replaced to use id
dom-modules that contain both name and is
| ### | |
| Unobtrusive JavaScript solution for polling in a Rails application | |
| Introduction: | |
| Add a polling-placeholder wrapper div to any partial and add a data attribute | |
| named poll that should be equal to "true" until you want to stop polling. | |
| The default polling frequency will be used unless you provide an "interval" data | |
| attribute which should be the number of milliseconds to use for the interval. |