Vagrant to 1.31 failure with old 0.8.10 vagrantfile

C:\Users\JulianMark3\foswiki-vagrant>vagrant up
C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/plugins/kernel_v1/config/vm.rb:35:in `[]': can't convert Symbol into Integer (TypeErro
r)
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/plugins/kernel_v1/config/vm.rb:35:in `forward_port'
        from C:/Users/JulianMark3/foswiki-vagrant/Vagrantfile:22:in `block in <top (required)>'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/config/v1/loader.rb:37:in `call'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/config/v1/loader.rb:37:in `load'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/config/loader.rb:104:in `block (2 levels) in load'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/config/loader.rb:98:in `each'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/config/loader.rb:98:in `block in load'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/config/loader.rb:95:in `each'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/config/loader.rb:95:in `load'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/environment.rb:267:in `config_global'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/environment.rb:519:in `block in action_runner'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/action/runner.rb:28:in `call'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/action/runner.rb:28:in `run'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/environment.rb:280:in `hook'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/lib/vagrant/environment.rb:135:in `initialize'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/bin/vagrant:74:in `new'
        from C:/HashiCorp/Vagrant/embedded/gems/gems/vagrant-1.3.1/bin/vagrant:74:in `<top (required)>'
        from C:/HashiCorp/Vagrant/bin//../embedded/../embedded/gems/bin/vagrant:23:in `load'
        from C:/HashiCorp/Vagrant/bin//../embedded/../embedded/gems/bin/vagrant:23:in `<main>'