The software depended on the presence of the visual indicator software, a paid option that was not selected by most airlines.[115] For example, Air Canada, American Airlines and Westjet had purchased the disagree alert, while Air Canada and American Airlines also purchased, in addition, the AoA value indicator, and Lion Air had neither.[116][117] Boeing had determined that the defect was not critical to aircraft safety or operation, and an internal safety review board (SRB) corroborated Boeing's prior assessment and its initial plan to update the aircraft in 2020. Boeing did not disclose the defect to the FAA until November 2018, in the wake of the Lion Air crash.[118][5][120][121] Consequently, Southwest had announced to pilots that its entire fleet of MAX 8 aircraft will receive the optional upgrades.[122][123] In March 2019, after the second accident of Ethiopian Airlines Flight 302, a Boeing representative told Inc. magazine, "Customers have been informed that AoA Disagree alert will become a standard feature on the 737 MAX. It can be retrofitted on previously delivered airplanes."[124]