Vue-Material navbar, Missing required prop: "to" - vue.js

Question

So the Vue-Material docs (https://vuematerial.io/components/bottom-bar) says it is possible to create a md-bottom-bar stuffed with md-bottom-bar-item, while being able to make md-bottom-bar-item act like a <router-link>
Their code can be seen right below "Seamless integration with Vue Router" (this is exactly what it's meant for by the way ^^), and my code looks like this :
<md-bottom-bar-item
id="messageRoute"
to="/Messages"
#click="stuff"
md-label="Notifications"
md-icon="message">
</md-bottom-bar-item>
<md-bottom-bar-item
id="settingsRoute"
to="/Settings"
#click="stuff"
md-label="Options"
md-icon="settings">
</md-bottom-bar-item>
These are tabs to a notifications list, and the settings page for my app.
The error I got when I click on an item is literally this (I got it 5 times though, beucause there's 5 items in my navbar) :
[Vue warn]: Missing required prop: "to"
found in
---> <MdButton> at src/components/MdButton/MdButton.vue
<MdBottomBarItem> at src/components/MdBottomBar/MdBottomBarItem.vue
<MdRipple> at src/components/MdRipple/MdRipple.vue
<MdBottomBar> at src/components/MdBottomBar/MdBottomBar.vue
<NavBar> at src\components\NavBar.vue
<App> at src\App.vue
<Root>
I got the same error without the #click='stuff' by the way, nothing to do with it.... I guess...
Is it about Vue-Material#1.0.0 (the one I'm using) being in beta or ? It feels like I'm doing what is showed in the doc, I even copy-pasted it and changed things so it would fit in my app.
For now I just did a goTo(path) methods, that just do this.$router.replace(path), but the bottom bar is not sync with Vue's router, with the md-sync-route attribute, like so :
<md-bottom-bar md-sync-route>
<!-- stuff -->
</md-bottom-bar>
Not a critical problem, but damn, why Vue.js, why ??? ^^'
And, what a troll :

Answer 1

Ok, this is interesting.
As the issue you gave me pointed out, this might be a version problem, but my vue version is 2.9.2 (checked it with vue -V). Nevermind, I still ran npm update -g vue, and the answer I got from the terminal... well :
+ vue#2.5.11
updated 1 package in 0.626s
Now everything works fine (router, to, etc...).
But why though ? Does vue-material uses a slightly different vue, or there's some parts that are redefined, like router link's behavior on certain element like md-bottom-bar-item ?
And why npm install couldn't fix that ? Well anyway, now it works, and my last questions exists probably because this framework is a beta and few things have to be done... or because I'm starting to do stuff with npm etc ^^
If you know something it would be helpful for me to know, feel free to tell me, I'd be glad to hear...

Answer 2

It will also happen in 1.0.0-beta-8, but there seems to be a commit to fix
https://github.com/vuematerial/vue-material/commit/6860d3a004b09baef751724c0d9bf1ebdf92b752