In Go time, that’s…really really old. (Even if it’s only 2 years old in calendar time.)
I don’t see a minimum Go version called out in any documentation I can easily find. Go 1.7’s big feature was adding "context", and transport.DialContext and dialer.DialContext almost certainly came along with that; http.ErrUseLastResponse is also a Go 1.7 feature; time.Until got added in Go 1.8. So it looks like Go 1.8 is the minimum.
In my experience Go has been pretty serious about their backwards compatibility guarantees and upgrading the Go toolchain version is pretty safe. For practical development you almost certainly want context in the standard library anyways and I’d encourage upgrading.