[scrollaway]

I never bothered to really look into it -- I suspect it's semi-public information. If I had to guess, lots of internal changes to make Redis behave better in AWS's architecture to do with containerization, EC2, S3/EBS, maintenance automation related stuff, instrumentation, etc.

Oh actually definitely some stuff related to their redis clustering system.

[buzer]

They also support encryption in transit. That part was open sourced recently, but hasn't made it into upstream yet (though it most likely will from sounds of it).