VirtualBox.app would no longer run

Results in About This Mac:

macOS Mojave
Version 10.14.1
MacBook Pro (Retina, 13-inch, Early 2015)

This hardware shipped the OS version 10.10 Yosemite, if I remember correctly.

In either the Mojave update or the High Sierra update (I think it wasn't as early as by the Sierra update), VirtualBox.app stopped being runnable. I'm pretty sure this was still functioning by the time El Capitan was running.

The VirtualBox.app appears grayed out when finding it on Spotlight. When hitting it, it won't start normally as it did once upon a time, and the message is:

You can't use this version of the application "VirtualBox
.app" with this version of macOS.

You have "VirtualBox.app" 5.0.0.

[?] [OK]

I guess I'll install an up to date build of the same major version 5. It's going to be a bit painful because I should back up the virtual machine before the update, and it's big. But...

Before I do that, can I get any better reporting message of the problem? Or do you know what is happening?

The binaries in /Applications/VirtualBox.app/Contents/MacOS/ seem to be all 64 bit.