cholling,
A while back I responded to a conversation about assignment submissions that @James was involved in.
That really doesn't help narrow it down 
The functionality is available right now in Canvas. It was deployed earlier this spring. What's happening in July is that they are forcing it on for people rather than it being behind a feature option.
The admin must go into Admin > Settings > Feature Options and enable "Assignment Allowed Attempts." If it is set to "On" then faculty will have that option on assignments automatically. If it is set to "Enable" then faculty will need to go into Course Settings > Feature Options and turn on the "Assignment Allowed Attempts" feature.
Then when you go to an assignment that has an Online or External Tool submission type, you will see the Submission Attempts box in the link that @kmeeusen provided.
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