There isn't an available release date yet - but, based on my years here, my best estimate for you would be sometime during the weekend of March 22nd - 24th. Its usually later in March and updates usually happen on weekends.
Thank you. I had this question today and looked high and low for a release date. I figured this was a good time to start a 2019 thread because this is a great place to look for assistance. Thanks again!
You're welcome. When it does get updated, we usually try to go back and update these answers so people know. Ill try to mark this one down and let you know.
@kellykero In case you haven't seen, the Extension section is ready. You can go here -
<a rel="nofollow" target="_blank" href="https://turbotax.intuit.com/irs-tax-extensions/">https://turbotax.intuit.com/irs-tax-extensions/</a>