It is currently impossible to reach out to all asset customers on-platform to inform them about critical updates, and bug-fixes for assets that they have purchased. There is no indication in Roblox Studio that assets have received an update, unless the user is already navigating the ‘Manage Plugins’ tab.
I needed something like this today because a recent change to EditableMesh completely broke features in my plugin UGC Makers Toolbox. If a customer does not see my tweet about the bug fix, and does not have ‘auto-update’ toggled then they may be stuck with broken features.
If Roblox addressed this issue creators would be able to contact all paying customers of a product that I am selling on the Creator Store and let them know about critical fixes to issues that are needed for the product they bought to continue working as intended.