If you moved to the Standard release no action needed - but you could now move back to targeted
If you did get a replacement NAMEEXT.DLL then no action needed, either "Update Now" or when the next update and the new DLL will replace the temporary one.
If you used some other workaround based on the DLL in the error - then "Update Now" to fix it
If you are seeing this error for the first time - then "Update Now" to get the latest version
After updating Project Pro – customers with the fixed versions should be on builds at or greater than 16.0.11727.20244
For the background to the issue read on ***
There is an issue with a recent update (June 2019) of the Project Professional click to run client for those in the targeted channels (Project Online Desktop client) that gives an error for Windows 7 users when connecting to Project Web App, either by opening the application and trying to connect to PWA, or if taking an action that would start Project, such as opening a plan from the Project Center into Project:
Error message - full text below
“The program can't start because api-ms-win-core-version-l1-1-0.dll is missing from your computer. Try reinstalling the program to fix this problem.”
This affects customers on targeted releases and only on Windows 7 - and can be overcome by reverting to the standard release for now, and if you understand that then go for it - if not then read on for other options...
We have a couple of workarounds for this issue and I'd suggest number 2 might be the best one to choose, as it keeps you at the same release level just in case you are benefiting from a recent fix for any of the Office products:
As this only affects the targeted channel you can revert to the standard release and then uninstall and re-install to get things working. To make these changes get your administrator to go to Office 365 Admin Center, then Settings, Organizational Profile and change release preferences to Standard Release under the Release track.
Contact support and we can supply a fixed NAMEEXT.DLL that will overcome the issue. Quote SP183696 to help identify the issue you are having.
Once we release the fix (hopefully we will make the July updates) then no action is needed - the right new DLL will be installed. If you take option 1 above then after the July updates you could change back to targeted release.
We have issued a Service Health Dashboard announcement, but only to customers who have opened cases - SP183696.
And again, this only affects Windows 7, and as a reminder, support for Windows 7 ends on January 14th 2020.