Welcome to this thread, Sergio Siles.

I appreciate your effort in asking for updates regarding the option to update multiple customers simultaneously.

As of this writing, the said option is still unavailable. Our developers may need to review this. In the meantime, I encourage you to share your ideas and opinion regarding this feature through our feedback forum. This will help convince our engineers to prioritize in developing this option in the feature. This link will route you to the Feedback forum site: https://feedback.qbo.intuit.com/.

To get in the loop about the latest news and product developments in QuickBooks, I encourage you to visit our Firm of the future site. 

Please add a comment below for any additional questions about managing customers in QuickBooks. Have a good one.