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Can I use a new Arc Fault / Ground Fault breaker with old wire like knob & Tube

Yes you can use new Arc Fault and Ground Fault breakers on older circuits with knob and tube wiring or old wiring as long as breaker is installed and holds.

But, note older knob and tube wiring shared neutrals and this will create havoc on Arc Fault and Ground Fault breakers. If you install the breaker and there is an issue with the wiring the breaker will trip right away.