Did SELinux have any dramatic changes in the last 20 years?

I'm a 4th year computer science student, currently enrolled in a course about operating system security. For the course we all have to do a 30 minute presentation about various topics, and I chose SELinux as I thought this would be a good opportinuty to learn about it. I'm having some trouble finding adequate references though. The book I found, "SELinux by Example: Using Security Enhanced Linux" by Frank Mayer, Karl MacMillan, David Caplan, seems to be what I'm looking …

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