What newer operating system on Mac will still support Elements 13? I have a friend who is hesitant to use a newer version of Elements but needs to upgrade a MacBook Pro which is currently running El Capitan!
MacOS Mojave 10.14 is the last version that could support pse 13 since some of it's included utilities are 32 bit.
Are you saying that 32 bit is new at Mojave or after Mojave? If so then perhaps he should stop at High Sierra? I will check to see if his laptop includes 32 bit.
Starting with macOS Catalina 10.15 Apple removed the ability to run 32 bit applications, so Mojave 10.14 and older will still run 32 bit applications. Even though pse 13 itself is 64 bit, some of the included utilities like the updater are 32 bit, so Catalina and newer will refuse to install pse 13.