I also received this email .  The problem is it is telling us to go to R15_69 and we have rolled back to R15_27 and it is working.  When we do the update it goes back to R15_71 and the slowness comes back.  It wont let us update to R15_69

Hello ,

We’re reaching out to you about a recent issue you reported: QuickBooks Desktop 2023 R16_36 & 2024 R15_69 – Slowness when opening or using a company file with attachments. Good news! We reviewed your case (15141469503), and we're happy to say this issue was resolved with our latest release of QuickBooks Desktop.

To make sure you have the most up-to-date information, please update your QuickBooks Desktop to the latest release.