Acknowledgments in Arxiv preprint I have recently submitted a paper to a journal, with the format required by the journal itself.

Now I am submitting on Arxiv a version of the paper with the same content but a different formatting (not the journal format, just a generic one).

I am wondering: should I keep the acknowledgments in this Arxiv preprint?
Yes, you should keep the acknowledgments. Whatever the acknowledged did to contribute to your paper is independent from the mode of dissemination – except when it clearly isn’t, e.g., when you acknowledge a reviewer whose suggestions improved the journal paper but could not be included in the Arxiv paper due to journal policies.

If an acknowledgment is required by somebody (e.g., by whoever funded your research), this requirement may also apply to publishing a preprint, i.e., you may even be forced to do this.

As for common practice, I have seen many Arxiv papers with acknowledgments and never noticed an acknowledgment being only present in the journal version (but then I never payed attention to this). I never removed acknowledgments for an Arxiv publication.