The SHERPA/RoMEO database makes the following distinction: preprints are all versions of an article that were written prior to the peer review, while postprints are all versions after the peer review process has been completed.
Publishers have different requirements when it comes to the publication of preprints and postprints. With respect to preprints, the decisive factor is often whether they can be archived or not. In the case of postprints, it is the appearance of the publication, in particular, that is important: many publishers only permit green open access if it is not the publisher's version-of-record that is self-archived, but rather a version that does not feature the publisher's own formatting and logo.
Preprint and postprint versions of published articles can also be found in the ZHAW digitalcollection, the repository of the ZHAW.
Räber, M., Heinzelmann, A., & Oliapuram, J. (2019). Analysis of a three-phase AC chopper with high power factor for the use in “PV-to-Heat” applications. ZHAW digitalcollection. https://doi.org/10.21256/zhaw-18668
Röcker, B., Rüegg, N., Glöss, A. N., Yeretzian, C., & Yildirim, S. (2017). Inactivation of palladium-based oxygen scavenger system by volatile sulphur compounds present in the headspace of packaged food. ZHAW digitalcollection. https://doi.org/10.21256/zhaw-4261
Accepted version, author accepted manuscript, postprint (not in published layout):
Nicoletti, C., & Läubli, T. (2018). Leg and back muscle activity, heart rate, performance and comfort during sitting, standing, and using a sit-stand-support with different seat angles. ZHAW digitalcollection. https://doi.org/10.21256/ZHAW-17602
Wildi, M., & Bundi, N. A. (2019). Bitcoin and market-(in)efficiency: A systematic time series approach. ZHAW digitalcollection. https://doi.org/10.21256/zhaw-19440
In accordance with the APA 7th edition, the repository where the text was found is stated rather than the publication in which an article or contribution appeared when citing preprint and postprint versions.
