One probably has to click “OK”, although this is not something I have found anywhere stated as such.
That warning is showing up because Apple is requiring that all developers upgrade their 32-bit versions to 64 bit, if they have not done that yet. The message pops up these days on Mac users for those with macOS Sierra 10.13.x and or Mojave 10.14.x (“x” being the installed version one has in one’s Mac): “ App is not optimized for your Mac and needs updating“.
