How can I fix the problem below ?
$ brew update && brew upgrade
Already up-to-date.
Error: Calling needs :cxx11 is disabled! There is no replacement.
Please report this to the weikengchen/caskformula tap:
/usr/local/Homebrew/Library/Taps/weikengchen/homebrew-caskformula/Formula/inkscape.rb:31
If reporting this issue please do so at (not Homebrew/brew or Homebrew/core):
https://github.com/weikengchen/homebrew-caskformula/issues