如何更新Go的Delve调试器?

How does one update their Go Delve Debugger? I"m receiving the following error when I try to set the api version:

unknown flag: --api-version

My dlv looks out of date:

$dlv version
Delve Debugger
Version: 0.11.0-alpha
Build: 

But I can't figure out how to upgrade it. I've tried go get -u github.com/go-delve/delve/cmd/dlv and go get -u github.com/derekparker/delve/cmd/dlv, but neither worked. I also tried the suggestion to make install:

$ git clone https://github.com/go-delve/delve.git $GOPATH/src/github.com/go-delve/delve
$ cd $GOPATH/src/github.com/go-delve/delve
$ make install

But that appears to have no effect:

$ dlv version
Delve Debugger
Version: 0.11.0-alpha
Build:

My go version is go version go1.10.1 linux/amd64 and my OS details are below:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 8.11 (jessie)
Release:    8.11
Codename:   jessie

This is copied from the issue I opened. I thought I'd cross post for greater visibility.