Since no Solaris systems existed before 1970, the timestamp field in the lastlog, utmpx, and wtmpx files in #OracleSolaris 11.4.72 has been redefined as an unsigned 32-bit int, where it was previously signed. This moves the range of possible timestamps from 1901–2038 to 1970–2106. The core OS software has been modified to reflect this, but other software may need changes to handle timestamps in these files with the highest bit set as being post-2037 instead of pre-1970.