Fix go version hint.
@@ -58,7 +58,7 @@ Prometheus will now be reachable at http://localhost:9090/.
### Building from source
To build Prometheus from the source code yourself you need to have a working
-Go environment with [version 1.5 or greater installed](http://golang.org/doc/install).
+Go environment with [version 1.8 or greater installed](http://golang.org/doc/install).
You can directly use the `go` tool to download and install the `prometheus`
and `promtool` binaries into your `GOPATH`. We use Go 1.5's experimental
