Hi richardhwi,
That's a great question! I'm glad to hear you're on the ball and prepared for the July payroll and tax table updates. Many of our users have already made the upgrade to QuickBooks Desktop 2019, so you're more than welcome to do that now. I recommend doing it before the update so you don't run into any delays running your payroll once the updates are released.
If you're on a subscription, an email would have been sent to you about upgrading. If you didn't see that email or your not on a subscription, the QuickBooks Desktop phone support team can lend a hand. Reach out at 1-877-772-9158 and you can reach Pro and Premier support 24/7. In the event you need Enterprise support, call from Monday to Friday between 9 a.m. and 8 p.m. EST.
Have a wonderful weekend! :)