- op : flip
  version :
    - checkpoint : Upgrade flip, add new attr [axis] and delete attr [dims]
      action :
        - add_attr : axis
          comment : The added attr 'axis' doesn't set default value
          default : paddle::none
        - delete_attr : dims
          comment : The attr 'dims' is deleted.

- op : grid_sample
  version :
    - checkpoint : Upgrade grid_sampler add a new attribute [mode]
      action :
        - add_attr : mode
          comment : In order to specify interpolation mode
          default : std::string("bilinear")

- op : trace
  version :
    - checkpoint : Upgrade trace add a new attribute [axis2]
      action :
        - add_attr : axis1
          comment : The added attribute 'axis1' is not yet registered.
          default : std::vector<float>{0.0f}
        - add_attr :
          name : axis2
          comment : The added attribute 'axis2' is not yet registered.
          default : std::vector<float>{1.0f}
        - delete_attr : dim1
          comment : The attribute 'dim1' is not recommend according to the specification 2.0.
        - delete_attr : dim2
          comment : The attribute 'dim2' is not recommend according to the specification 2.0.