Microsoft has just released a major new revision to these cmdlets, version 5.0.0. The details can be found over on GitHub at: https://github.com/Azure/azure-powershell/releases/tag/v5.0.0-November2017.
This is a major update, as evidenced by the major version number change (from 4.x.x to 5.x.x). Additionally, there are several breaking changes - changes that could break your code if you update just the module itself. You can see a list of updates at: https://github.com/Azure/azure-powershell/blob/release-5.0.0/documentation/release-notes/migration-guide.5.0.0.md.
If you are using Azure cmdlets - then you probably have some work to do to update to the new cmdlets. But all in all, such is the price of progress.