If you want to guarantee the preservation of data in an inactive MEGA account, you can upgrade to PRO. About 20 were made before break-up of Yugoslavia. Prototypes were impressed into regular service, however there is no data of them being used in combat. A variant of this modification, https://mega-dm32975.tribunablog.com/mega555kf7lsmb54yd6etzginolhxxi4ytdoma2rf77ngq55fhfcnyid-onion-29138531