In an effort to discourage cheating in terms of how soon Trophies are awarded, the PlayStation Network requires consoles to maintain an accurate time and date setting before a digitally downloaded game can be started, which also extends to virtually all physically released software for the PS4 and certain physical games for the PS5. Without a connection to PlayStation Network, consoles would rely on a CMOS battery to maintain the date and time. If a console is unable to obtain an accurate date and time from PlayStation Network due to loss of connectivity and CMOS battery charge combined, games can be rendered unplayable on it, leading critics to decry this anti-cheat system as a form of always-on DRM and a threat to video game preservation upon discovery of this issue, known as the C-bomb,[26] several months after the PlayStation 5's launch, as Sony was contemplating an equally controversial decision to shut down the PlayStation Store for previously discontinued systems that used it.[27][28][29] In late September 2021, Sony resolved the C-bomb issue for the PS4 with firmware update 9.0.0, so that an inability to obtain an accurate date and time from PSN would only disable time-stamping of Trophies instead of blocking startup of games.[30][31] Sony later resolved the same issue for the PlayStation 5 in November, allowing all physical and digital PS4 and PS5 games to run without any need for an accurate date and time reading from PSN, except for PlayStation Plus games, which require online verification to access them.[32]