HACKING.md: expect snapcraft 8.x

HACKING.md

@@ -70,31 +70,22 @@ go get ./... && ./get-deps.sh
 
 The easiest (though not the most efficient) way to test changes to snapd is to
 build the snapd snap using _snapcraft_ and then install that snapd snap. The
-[snapcraft.yaml](./build-aux/snapcraft.yaml) for the snapd snap is located at 
+[snapcraft.yaml](./build-aux/snap/snapcraft.yaml) for the snapd snap is located at
 [./build-aux/](./build-aux/), and
-can be built using snapcraft either in a LXD container or a multipass VM (or
-natively with `--destructive-mode` on a Ubuntu 16.04 host).
+can be built using snapcraft.
 
-> Currently, snapcraft's default track of 5.x does not support building the 
-snapd snap, since the snapd snap uses `build-base: core`. Building with a 
-`build-base` of core uses Ubuntu 16.04 as the base operating system (and thus 
-root filesystem) for building and Ubuntu 16.04 is now in Extended Security 
-Maintenance (ESM, see 
-[Ubuntu 16.04 LTS ESM](https://ubuntu.com/blog/ubuntu-16-04-lts-transitions-to-extended-security-maintenance-esm)),
-and as such only is buildable using snapcraft's 4.x channel. At some point in the future,
-the snapd snap should be moved to a newer `build-base`, but until then `4.x` 
-needs to be used.
+Snapcraft 8.x or later is expected.
 
-Install snapcraft from the 4.x channel:
+Install snapcraft:
 
 ```
-sudo snap install snapcraft --channel=4.x
+sudo snap install snapcraft
 ```
 
 Then run snapcraft:
 
 ```
-snapcraft
+snapcraft --channel=latest/stable
 ```
 
 Now the snapd snap that was just built can be installed with:
@@ -111,29 +102,15 @@ can either use `snap revert snapd`, or you can refresh directly with
 #### Building for other architectures with snapcraft
 
 It is also sometimes useful to use snapcraft to build the snapd snap for
-other architectures using the `remote-build` feature. In order to build
-remotely with snapcraft, make sure you have at least version `6.x` installed:
-if the command `snap info snapcraft` shows that you are running an older
-version, upgrade with:
+other architectures using the `remote-build` feature.
 
-```
-snap refresh snapcraft --channel=latest/stable
-```
-
-Now you can use remote-build with snapcraft on the snapd tree for any desired 
+You can use remote-build with snapcraft on the snapd tree for any desired
 architectures:
 
 ```
 snapcraft remote-build --build-for=armhf,s390x,arm64
 ```
 
-And to go back to building the snapd snap locally, just revert the channel back
-to 4.x:
-
-```
-snap refresh snapcraft --channel=4.x/stable
-```
-
 #### Splicing the snapd snap into the core snap
 
 Sometimes while developing you may need to build a version of the _core_ snap