The download at that specific URL is no longer available. To obtain the current security or cumulative updates for SQL Server instead of that retired package, use the active download channels provided for the relevant SQL Server version.
For SQL Server 2016 SP3 GDR (the package that used the now-removed link), the replacement is the current security update available from the Microsoft Download Center via the link documented in the KB article. Use the “Download the package now” link in that article to get the latest supported build rather than the retired one.
If the goal is to keep SQL Server updated in general, always obtain the latest cumulative or security update from the official update pages instead of relying on older direct-download URLs, as those may be removed when superseded.
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