I found this definition on Wikipedia(https://en.wikipedia.org/wiki/Drop-in_replacement ) about drop in replacement "Drop-in replacement is a term used in computer science and other fields. It refers to the ability to replace one hardware or software component with another one without any other code or configuration changes being required and resulting in no negative impacts." While one may be able to do more and possibly better with SAS Viya , continue to use old code with necessary/essential changes, in my experience it is not a drop in replacement. Programmers do have some changes , but for SAS 9.4 Administrators it requires substantial learning and facing challenges.
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