Go 1.3 is unmaintained/unsupported upstream

[John Lenton]

Go 1.3.3, which we are shipping in Vivid, is unmaintained upstream¹
(yes, despite being released less than six months ago).

Would it be possible to move to 1.4 in vivid? This wouldn't fix the
fact that it will become unmaintained in Vivid's timeframe, but at
least we can get the bugs we find during development fixed upstream.


1. https://github.com/golang/go/issues/9866#event-235479734