https://en.wikipedia.org/wiki/Scientific_Linux says "In April 2019, it was announced that Scientific Linux would be discontinued, but that maintenance will continue to be provided for the 6.x and 7.x releases through the end of their lifecycles."
lwn synopsis at https://lwn.net/Articles/786422/ .
Note: 'Scientific Linux' is a Red Hat-derived distribution. Users are migrating to CentOS.