Real stats on which versions of Rust are actually used?

As a library author I’m not sure which old versions of Rust I should support. The user survey shows that most use latest stable, but ~5% use some older version. If I want to support 99% of Rust users, which version should I target? Debian tends to freeze Rust versions for years. Do people actually use Debian’s Rust, or can it be ignored?

So I’m wondering, are there any precise stats of Rust version usage? For example, could crates-io server log versions of Cargo that make API calls to it, and report the versions it sees similarly to the Android version dashboard?

3 Likes does log the Cargo versions, and @sgrif has published some data on it in the past. As far as I’m aware it has to be manually collected at this point, but maybe it’s something that could be automated and added to the UI?

EDIT: And here’s an existing issue about it:


I do, but I don't expect the latest crates off of to build with it. I expect Rust software packaged in Debian to build with it.


I originally did, but stopped because I was tired of having a super old version…

As best I can tell, there is very little interest in support for old compiler versions, for now at least. See this thread.