Azure Monitor classic alerts retirement date extended to August 31st, 2019

Azure Monitor classic alerts retirement date which was originally scheduled for June 30th, 2019 is being extended to August 31st, 2019 to provide customers more time to voluntarily migrate their classic alerts. You can migrate your classic alerts today using the migration tool. After August 31st, 2019 we will perform an automatic migration on your behalf.
Source: Azure Roadmap