Are all of your dependencies up to date? This might be caused by overlapping caniuse-db versions.

Yes. Even after updating all dependencies it still throws this error. I am sad. 😢

That's odd. @sylvainpolletvillard had this issue earlier and it was resolved by updating caniuse-db manually to the latest version. Does this work for you?

How does one go about doing this?
npm i caniuse-db ?

Yeah, the current version is 1.0.30000605; Fyrd/caniuse@67737db

Yes, I got the same issue today and solved it with npm update caniuse-db
It works with caniuse-db version 1.0.30000605

Same error here.
I found that it comes from https://github.com/ben-eb/postcss-merge-rules, that uses caniuse-api@1.5.2.

For now, I only exclude merge-rules from my optimization process:
cssnano({ mergeRules: false })

solution:
npm i caniuse-db --save with npm 3+

Same error, npm i caniuse-db --save fixed it

@kristoferjoseph hm, thanks, that work for me

I'm still getting this error, even with the autoprefixer optimisation disabled and after running npm update caniuse-db. I've purged my node_modules directory as well.

The error I'm specifically receiving is Unknown version 0 of and_chr

@ScottSmith95 Does the latest release of browserslist resolve this issue for you? browserslist/browserslist#110 (comment)

Yes, looks like this issue is resolved for me now.

Same error here. Had to pin cssnano@3.9.1. Everything after 3.9.1 throws the error mentioned above.