I’m assuming That by “update the device handler” you mean to change the device handler that a specific device is assigned to? Not actually change the code of an existing device handler?
If that assumption is correct:
sign into the IDE and get to the list of your devices
click on the name of the device you want to reassign. That will open its details page.
go all the way down to the bottom of the details page and click the red EDIT button. That will take you to a page where you can assign the device to one of the other device handlers in your account’s library.
If my assumption is incorrect, and you’re actually asking how to publish a new device handler to your account, see the custom code FAQ:
