On October 1st, 2020, API version 2020-10 will be released and support for custom and public apps calling the 2019-10 API version will be removed. The 2020-01 API version will become the last supported stable version.
To minimize merchant impact, apps that continue to use the unsupported API after October 1st will be delisted from the Shopify App Store and have new installations blocked.
This means that only the most proactive integration platforms will continue to work with Shopify.
For our clients that have extensively used Shopify apps to expand the functionality of their store please keep an eye out in the coming month for breaking changes.