```ruby
require 'redmine_charts/line_data_converter'
require 'redmine_charts/pie_data_converter'
require 'redmine_charts/stack_data_converter'
require 'redmine_charts/utils'
require 'redmine_charts/conditions_utils'
require 'redmine_charts/grouping_utils'
require 'redmine_charts/range_utils'
require 'redmine_charts/issue_patch'
require 'redmine_charts/time_entry_patch'

module RedmineCharts

  def self.has_sub_issues_functionality_active
    ((Redmine::VERSION.to_a <=> [0,9,5]) >= 0) or (Redmine::VERSION.to_a == [0,9,4,'devel'])
  end

end```

Fix subtasks problem in Redmine 0.9.x
user
```ruby
require 'redmine_charts/line_data_converter'
require 'redmine_charts/pie_data_converter'
require 'redmine_charts/stack_data_converter'
require 'redmine_charts/utils'
require 'redmine_charts/conditions_utils'
require 'redmine_charts/grouping_utils'
require 'redmine_charts/range_utils'
require 'redmine_charts/issue_patch'
require 'redmine_charts/time_entry_patch'

module RedmineCharts

  def self.has_sub_issues_functionality_active
    ((Redmine::VERSION.to_a <=> [1,0,0]) >= 0)
  end

end```
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