The Materials Project has been performing calculations of materials since 2011. As computing power increases and the state-of-the-art in scientific computation advances, some of our older calculations no longer meet our current quality standards, or have had other technical issues associated with them.
In 2019 we have decided to implement a formal deprecation process, whereby we can remove an older calculation and replace it with a newer one. In the process, we will hide this older calculation from our default search results, but in the interests of transparency all old calculations remain accessible via our programmatic API or via direct access on the website.
Deprecations are not retractions. However, if a material only had a single deprecated task associated with it, that material will no longer have data associated with it on the website until the updated calculation is completed. We are running these calculations continuously, with the website database being updated around once a month.
We will update this document with a full list of deprecated calculations ("task_ids") in due course, along with the reason for their deprecation.
If you have any questions about the deprecation process, or if there's a material ID you're interested in that you can no longer find, please ask us on our community forum and we'd be happy to help.