the data_class option was not introduced in 2.4
bug #3415 [#3334] the data_class option was not introduced in 2.4 (xabbuh)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #3415).

Discussion
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[#3334] the data_class option was not introduced in 2.4

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets |

Commits
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c96e6eb [#3334] the data_class option was not introduced in 2.4