[…] Many people will never know about PROC DELETE's near-death experience. Even though it's been lurking within Base SAS for decades, PROC DELETE could not be allowed to continue as-is. SAS software and infrastructure has evolved considerably to take advantage of new hardware and operating system capabilities. Even established SAS procedures and functions must be refreshed continuously to keeping them humming along. If a feature in the software becomes disused (especially something that is undocumented/unsupported), developers have to decide whether to invest the time to refresh it and test it, or "put it down" to prevent unstable behavior. …