With the release of London in September 2018, ServiceNow will no longer support the Istanbul Family.
Customers are required to upgrade instances on Istanbul to a supported family version. Instances still on Istanbul will be scheduled for upgrade to the highest available version of London during Q3 and Q4 2018. However, we encourage customers to plan now and upgrade to the highest available version of a supported family, including Jakarta and Kingston. For more information about upgrading, see the ServiceNow product documentation.
Customers who still have instances on Istanbul will receive communications noting the schedule when ServiceNow will upgrade their instances. If you have questions or issues associated with your scheduled upgrade, contact ServiceNow through your Communication (COM) record.
For the latest information, visit the Patching and End of Life Upgrades Community.