Hey @Alain,
The tax rate-related features you describe may be possible with WooCommerce itself or some other WooCommerce add-on, but none of our add-ons, including Event Tickets Plus, handle payments themselves and thus do not provide any tax-addition features like you mention.
As for why you do not have an update for Event Tickets Plus, the free update to Event Tickets Plus is only offered for existing license holders of WooCommerce Tickets, or any other ticketing add-ons like EDD Tickets.
For you, the only WooCommerce Tickets license I see of yours is one that expired more than a year ago. Is this accurate? Have you recently purchased or renewed a license for WooCommerce Tickets, perhaps under a different account name or something?
Thanks!
George