RC3 is out with a few deps changes now that Ecto 3.0.0 is out. To update existing RC apps, simply remove an explicit :ecto dep from your mix.exs, and update your :phoenix_ecto and :ecto_sql deps to the following:
...,
{:ecto_sql, “~> 3.0-rc”},
{:phoenix_ecto, “~> 4.0”},
Also be sure to grab the latest project generator:
$ mix archive.uninstall phx_new
$ mix archive.install hex phx_new 1.4.0-rc.3
To list presences, you still need the stateful object, ie presence.list(callback), so it doesn’t make since to mix and match the pure functional and instanced based APIs.
To be clear, a closure is always required in either old or new APIs because you must decide how to list your present users, given all their unique tabs/devices.
I’m aware the stateful object is needed here and I’m not trying to argue against it. What I don’t like by the current way of not passing the presence object to the callback is that the presence object needs to be in scope at the place the callback is created. When the callback is created elsewhere one currently needs to wrap it in another closure just to get access to the presences object, which could simply be given to the callback.
// Somewhere in the code
let myPresenceUsageCallback = presence => {
console.log(presence.list())
}
// Pass myPresenceUsageCallback around to wherever the following is executed
let presence = new Presence(channel)
presence.onSync(myPresenceUsageCallback) // won't work as of now
// will work, but seems unnecessary complication of the api
presence.onSync(() => myPresenceUsageCallback(presence))
Oh I see. the updated_presences plural through me off. I see how this would be convenient, but I find the current usage clearer. Passing itself in as an argument that you call off itself may confuse callers that the provided argument is different from the instance, so the extra 12 keystrokes is a small price to pay 
I’ve been checking the phoenix releases page almost every day for over a month, and just saw that the new release was published 2 hours ago. Super excited that Phoenix 1.4.0 stable is finally out!
Great
btw, the upgrade guide at Phoenix 1.3.x to 1.4.0 Upgrade Guides · GitHub still mentions
{:phoenix, "~> 1.4.0-rc", override: true}
Super nice, congrats! 
One small thing: the blog post says to add {:plug_cowboy, "~> 2.5"}, but last version is 2.0.0.
