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I run Mojave for safety. Mba 2017 (only slightly cpu diff from 2012), mbp 2014
 
As I said, this is my test machine. I use it to check out new versions of macOS before putting it on computers I'm actively using. Looking at replacements for 32-bit apps and trying them out on Catalina is one of the things I need to start doing. I'm wanting to know if there are issues running Catalina on this older hardware before I jump.
 
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