New Quizzes had been slated to replace Classic Quizzes in 2024 but Instructure has delayed the hard cutover and hasn't set a new date for the forced switch to occur. Faculty can choose to use New Quizzes, which has more question types and quiz setting than Classic Quizzes, any time. However, you do have select Classic or New for an entire course - you can't make one quiz using Classic Quizzes and another using New Quizzes.
Feature Comparison: Classic Quizzes and New Quizzes. The document is updated by Instructure as they continue to perfect New Quizzes and there are links to more information about those elements still under development.
New Quizzes Essentials On-Demand Course - This 90 minute recording is available on the Canvas Training Portal. Search for "New Quizzes Essentials" or, on the Training Portal homepage, scroll to Building Block Basics.