how to write this rule? (help)

[up4k]

Not sure what you mean. There's no such limitation!

I mean that rules like RULE_OP_MANGLE_APPEND_MEMORY or RULE_OP_MEMORIZE_WORD can be used with -j or -k only, and not in rulesets. As I understand from this thread, hashcat legacy hasn't such limitation. But now I think that I misunderstood it, and legacy version of hashcat also can't use rulesets with M or 4 rules.