Currently, campuses using Turnitin with Canvas have two integration options -- LTI, and/or the "Legacy" integration which enables Turnitin Originality Check reports as a feature of Canvas' Assignments tool. My understanding is that the Legacy integration was developed and is maintained by Instructure, and that this Legacy integration is dependent on Turnitin APIs which will be deprecated sometime in the next six-twelve months (outlined by Turnitin at Turnitin - API & Integration Plans). This page includes some detailed information about LMS "Integrations Developed by the Turnitin Team," but does not include Canvas (presumably because this integration was developed by Instructure, and not Turnitin?)
The Turnitin API and Integration plans page linked above state that the current Turnitin Legacy APIs will be replaced with "a variety of new toolsets for integrations...including SDKs and new APIs". Although these SDKs/APIs have not yet been released, so their full functionality is still unknown, I would think that there is a possibility for Instructure to update the current "Legacy" integration to maintain its existing functionality while using the new APIs. My question for Instructure is: will you be working to utilize these new APIs to maintain the current Turnitin integrations, or will Canvas support for Turnitin shift to the LTI tool exclusively?
My campus has a preference for the Legacy integration for a variety of reasons, but may begin to shift our resources towards LTI integration if that's our only path forward with Canvas and Turnitin. However, my hope is that Instructure will leverage the new Turnitin APIs to maintain the current deep integration between Canvas Assignments and Turnitin.