[checkup v2.0.0](https://github.com/sourcegraph/checkup/releases/tag/v2.0.0) was released on April 29th, 2020, but it's not installable via `go get`: ``` $ go get github.com/sourcegraph/checkup@v2.0.0 go get github.com/sourcegraph/checkup@v2.0.0: github.com/sourcegraph/checkup@v2.0.0: invalid version: module contains a go.mod file, so major version must be compatible: should be v0 or v1, not v2 ``` And when a simple `go get github.com/sourcegraph/checkup` is run with no [version query](https://golang.org/ref/mod#version-queries), `v1.0.0` is installed, despite it not being the most recent release. The reason is that Go modules are being used, and once a module hits major version 2 or beyond, a major version suffix is required. A major version suffix can be added to this repo by creating a `v2` directory for v2 code (for a full worked example, see the "Publishing v2 and beyond" section of the "v2 and Beyond" article below). For further detail, please see: - [Go Modules Reference: Major Version Suffixes](https://golang.org/ref/mod#major-version-suffixes) - [Go Modules: v2 and Beyond](https://blog.golang.org/v2-go-modules)