Upgrading from the legacy widget is just as simple as replacing the old script with the new one, which you can find here. Since V2 mostly tracks activity using links instead of 3rd party cookies, you can also freely remove any ICS cookie tracking scripts that were previously necessary, further simplifying the integration. The new links generated by V2 also will work retroactively with any legacy invites so you can upgrade to V2 without having to worry about creating a new campaign or missing out on any activity from old invites
If you’re using a direct JS installation of V2, refer to this guide.
If you’re using Shopify, you can reference this one.
Finally, if you’re not ready to fully commit to the change, you do always have the option of using the V2 script to load the legacy widget. For more information on that process, please see: Loading the legacy widget with the V2 script