yeah, with v5 of the API, all channel names have to be converted over to channel ID (users now uses ID as well)… you can convert then using the /users?login= endpoint…
so for instance, to get the channelId for aero2k13 you would make a call to /users?login=aero2k13 and it will return some json with the channel ID included…
as for how to convert the version of the api you are currently using to v5, you’ll unfortunately have to just read the docs and make adjustments as necessary… you may still have a little bit of time if you were using v3… the time table is here.
Hope this helps you out some