The Central Bank of Bolivia launched the Billetes de Bolivia mobile application to let the public quickly verify the validity of Series B BOB 10, BOB 20 and BOB 50 banknotes, including checks against banknotes disabled after a cargo aircraft accident. Only 17.1 million banknotes transported on the Transporte Aéreo Boliviano (TAB) Hercules C-130 that crashed on 27 February have been invalidated, with each note identified by serial number, while the vast majority of Series B notes in circulation remain valid legal tender. The app, available free on the App Store and Google Play, lets users scan a banknote or manually enter its serial number and works without an internet connection; it complements an online serial-number verifier the Central Bank made available on its website on 28 February. The Central Bank and the financial system will continue to identify and perforate invalid banknotes that reach their cash operations, and the public was urged not to reject Series B notes without verification. Central Bank President David Espinoza acknowledged that older people and others without access to technology may not be well served by digital tools and committed to develop additional verification mechanisms for those groups.