anchor.diff:          {shares, [string]},
           {deleted, boolean},
           {parent_uuid, string},
  +        % fields: references and symlink_value have been added in this version
           {references, #{string => [string]}},
           {symlink_value, string},
           % field dataset_status has been added in this version
  
positive.code:         {provider_id, string},
          {shares, [string]},
          {deleted, boolean},
          {parent_uuid, string},
          % following fields have been added in this version:
          {references, #{string => [string]}},
          {symlink_value, string}
      ]};
  get_record_struct(12) ->
      {record, [
  
negative.code:     ProviderId, Shares, Deleted, ParentUuid
  }) ->
      {11, {?FILE_META_MODEL, Name, Type, Mode, 0, ACL, Owner, IsScope,
          ProviderId, Shares, Deleted, ParentUuid
      }};
  % NOTE: there are 2 function clauses upgrading from version 11 to 12
  % because 21.02-alpha7 introduced a bug which could result in documents persisted with wrong number of fields
  upgrade_record(11, {?FILE_META_MODEL, Name, Type, Mode, ProtectionFlags, ACL, Owner, IsScope,
      ProviderId, Shares, Deleted, ParentUuid, References, SymlinkValue
  }) ->
      {12, {?FILE_META_MODEL, Name, Type, Mode, ProtectionFlags, ACL, Owner, IsScope,
          ProviderId, Shares, Deleted, ParentUuid,
          % fields: references and symlink_value have been added in this version
          References, SymlinkValue,
          % field dataset_status has been added in this version
          undefined
      }};
  upgrade_record(11, {?FILE_META_MODEL, Name, Type, Mode, ProtectionFlags, ACL, Owner, IsScope,
      ProviderId, Shares, Deleted, ParentUuid
  }) ->
      {12, {?FILE_META_MODEL, Name, Type, Mode, ProtectionFlags, ACL, Owner, IsScope,
          ProviderId, Shares, Deleted, ParentUuid,
          % fields: references and symlink_value have been added in this version
          #{}, undefined,
          % field dataset_status has been added in this version
          undefined
      }}.
  