Is "2013-08" the latest REST API version or is the documentation outdated?

Question

I'm wondering if the Azure Notification Hubs REST API documentation is
still correct and up-to-date or if there is already a newer API version than "2013-08" that can be used.
All the single pages show "Updated: February 26, 2015", but I guess it was just a meta data update of all the pages, since the API version didn't change,
it's still "2013-08". Is this intentional because the API didn't change or was it forgotten to update the API version?
Here (and here)
is an example for the REST API usage from Elio Damaggio which uses "2013-10" as the api version. I tried all possible api version values in the format "yyyy-mm" from "2013-10" to "2015-03" and the following
were working: "2013-10", "2014-01", "2014-05", "2014-08", "2014-09", "2015-01". Are there actual changes to the API and if so, aren't they officially supported or what is the reason for the
old API version in the documentation? 
Is the API version "2015-01" officially supported and can I find the documentation for it or am I stuck with API version "2013-08"? Or
aren't there any changes worth updating the documentation?
Moreover the documentation for "Read All Registrations of a Channel" states to use
following request URI, which doesn't work: https://{namespace}.servicebus.windows.net/{NotificationHub}/registrations/?$filter=DeviceToken eq ‘{deviceToken}’&api-version=2013-08
Even more confusing, the german version uses double quotes, which doesn't work either: https://{Namespace}.servicebus.windows.net/{Benachrichtigungshub}/registrations/?$filter=DeviceToken
eq "{Gerätetoken}"&api-version=2013-08
I found out that the correct request URI must be like this to work: https://{namespace}.servicebus.windows.net/{NotificationHub}/registrations/?$filter=DeviceToken+eq+'{deviceToken}'&api-version=2013-08 ,
so + instead of spaces and '' (apostrophe / straight single quote - U+0027) instead of ‘’ (single curved quotation marks - U+2018 and U+2019) or "" (straight double quote - U+0022), e.g. https://myServiceBusNamespace.servicebus.windows.net/myHub/registrations/?$filter=DeviceToken+eq+'2ED202AC08EA9033665E853A3DC8BC4C5E78F7A6CF8D55910DF230567037DCC4'&api-version=2013-08
Is the documentation just wrong by mistake or is it not up-to-date? How are people even using the REST API without a 100% correct documentation? Is
there something I am missing? Do you get a manual when you buy a Azure Notification Hubs subscription or is the REST API not even supported officially?

Answer 1

The latest version is 2015-01. All or most of features works with starting version 2013-08.
Version in documentation indicates that minimum version required for working that feature. Hence, all documentation is pointing to 2013-08.
You should do the URL encoding before making http request. Otherwise special characters such as blanks and punctuation are passed in an HTTP stream without encoding, they might be misinterpreted. Hence your request failed due to space. You can use the following
method to do the URL encoding.
https://msdn.microsoft.com/en-us/library/4fkewx0t%28v=vs.110%29.aspx
Yes, REST API is fully supported. May be there could be few gaps or bugs. We are putting constant efforts to fix all bugs as we find and improve it further.
Thanks,
Sateesh
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