In January,Amazon Web Services announced the availability of longer IDs for EC2 instances and reservations. As of March 7, 2016, and newly created AWS accounts will use longer EC2 instance and reservation IDs by default in the following regions: US East (Northern Virginia),US West (Oregon), US West (Northern California), or EU (Ireland),and EU (Frankfurt). In other regions, recent accounts will use longer EC2 instance and reservation IDs by default starting in mid-April 2016.
Source: amazon.com