Change effective on 21 April 2016
Heroku has added support for Go v1.6.2.
This is now the default version of Go when
go1.6 is specified in an application’s
Godeps/Godeps.json file (for godep),
$GOVERSION (for GB) environment variable, or
vendor/vendor.json file (for govendor) and will be used on next push.
This version of Go includes fixes to the compiler, runtime, tools, documentation, and the mime/multipart, net/http, and sort packages. See the Go 1.6.2 milestone on the issue tracker for details.