Brew cask. Hold Skype update You know new Skype even for Mac is written on Electron and working slow. But old native version is still working. 

Unfortunately brew cu -a https://github.com/buo/homebrew-cask-upgrade updates it to new one. Is it possible to hold version of this package (disable update) like aptitude hold package in debian?
The homebrew syntax would be "brew pin skype", unfortunately, there is no "pinning" in "brew cask" - so, no.