At this time, we don't have an exact time line as to when the Excel 2019 will be compatible with QBDT. But QuickBooks is constantly updating, rest assured that we will notify you through an email blast or next release. I'll also update you in this post once we get the update as well.
Meanwhile, Microsoft Office 2010 and Office 2013, 2016, and 365 (including Outlook 2010 and Outlook 2013) on both 32 and 64 bit are currently supported in QuickBooks Desktop 2019. However, Office and Excel 2019 are currently unsupported.
For more in-depth information about the system requirements, you can check out this great article: QuickBooks 2019 and Enterprise Solutions 19.0.
Also, to keep you notified as to what's new and what's coming, you can visit our blog: QuickBooks Firm of the Future blog.
Feel free to click the Reply button if you have other questions. I'm always here to help.