If you are unaware, older versions of the Azure Storage API will be turned off in December 2015. This means that any of your applications that use these older versions will stop working. If you are accessing the Storage API through an SDK then you most likely just need to rebuild with a newer supported version. If you are accessing the REST API directly then you will need to ensure that the code changes to support the newer API versions.
Full details of the changes can be found at: http://azure.microsoft.com/blog/2014/08/04/microsoft-azure-storage-service-version-removal/