I assume you mean "add-ons"? All add-ons have to be built (compiled) specifically for each version of AC, as they utilize a variety of common information. So, you cannot simply copy an add-on from AC 20 to AC 21 and expect it to run. The developer would have to recompile it for AC 21.
AC 28 USA and earlier • macOS Sequoia 15.3, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB
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