Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 70; Flight Crew Type 9000
Confusion; Situational Awareness; Communication Breakdown
Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
General None Reported / Taken
Environment - Non Weather Related; Human Factors
I removed my mask/facial covering upon boarding an empty aircraft and stowed my personal belongings in the cockpit. The B Flight Attendant asked why I wasn't wearing a mask in the cabin. (Again; the aircraft was empty; except for the six-person crew.) I stated it was not required when not in view of customers.  She said it was. I checked my manual updates and sure enough she was correct. I notified the Flight Attendant that I had seen the [update]. Flight departed on time and landed safely in ZZZ.
Air carrier Captain self reported not following the latest update regarding face mask policy.