Lets be clear about box version error

lib/vagrant-lxc/action/handle_box_metadata.rb

@@ -3,6 +3,7 @@ module Vagrant
     module Action
       # Prepare arguments to be used for lxc-create
       class HandleBoxMetadata
+        SUPPORTED_VERSIONS = [2, 3]
         def initialize(app, env)
           @app    = app
           @logger = Log4r::Logger.new("vagrant::lxc::action::handle_box_metadata")
@@ -51,8 +52,10 @@ module Vagrant
         end
 
         def validate_box
-          if [2, 3].include? @box.metadata.fetch('version').to_i
-            raise Errors::InvalidBoxVersion.new name: @box.name
+          unless SUPPORTED_VERSIONS.include? @box.metadata.fetch('version').to_i
+            raise Errors::IncompatibleBox.new name: @box.name,
+                                              found: @box.metadata.fetch('version').to_i,
+                                              supported: SUPPORTED_VERSIONS.join(' and ')
           end
 
           unless File.exists?(template_src)

lib/vagrant-lxc/errors.rb

@@ -14,8 +14,8 @@ module Vagrant
       class RootFSTarballMissing < Vagrant::Errors::VagrantError
         error_key(:lxc_invalid_box_version)
       end
-      class InvalidBoxVersion < Vagrant::Errors::VagrantError
-        error_key(:lxc_invalid_box_version)
+      class IncompatibleBox < Vagrant::Errors::VagrantError
+        error_key(:lxc_incompatible_box)
       end
     end
   end

locales/en.yml

@@ -33,6 +33,10 @@ en:
         For more information on the failure, enable detailed logging by setting
         the environment variable VAGRANT_LOG to DEBUG.
 
+      lxc_incompatible_box: |-
+        The base box you are trying to use is not compatible with the installed
+        vagrant-lxc version. Supported box versions are %{supported} but %{found} was found.
+
       lxc_template_file_missing: |-
         The template file used for creating the container was not found for %{name}
         box.