I put the keyValueStore class 2.20 version on my project and I don´t touch anything of it.
On B4i all worked well but during compilation in Xcode I have 4 issues in this class.
My Mac is Mac Mini 2014 running MacOS Mojave and my Xcode version is 10.1
I also have the latest version of B4i (5.50) and the latest version of mac builder