I'm not quite sure what impelled your opening question. Certainly EveryMac lists 6.0.7 to 7.5.5 for the Classic. However, an 8-MHz 68000 Mac with 1-4MB of RAM is already breathless under 7.5, and hides under the table if you even think about putting 7.5.5 onto it. I find that a Classic is happiest under the 'constructed' 7.1.3, and even then does not do as well as a 68030 Mac with 7.1.3 because of the CPU difference. A Classic chokes on obligatory 32-bit stuff.

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