Grand Theft Auto III may have been out for a while now, standing as a classic in the eyes of many gamers. However, despite its age, the game has received a new rating from the Australian Classification Board for one sole reason, essentially.
Indeed, the game has been updated with an R18+ rating due to "Sexual activity related to incentives and rewards."
Interestingly, as OnlySP notes, and as originally reported by ComicBook.com, the game is listed as "MODIFIED" on the ACB's website. This could be for multiple reasons, though the most likely possibility is that the game that received the new R18+ rating could be a version that includes mods from the community, though this is unclear given no confirmation or statement from Rockstar.
Also interesting is that the original author listed on the ACB's website was DMA Design, whereas it is now Rockstar North.
The ACB provides multiple criteria for the game's rating, including Themes, Violence, Language, Drug Use, Nudity, and Sex. While Themes and Violence were listed as having a "Strong Impact," Language and Drug Use were described as having a "Mild Impact." As suggested earlier, Sex was called out for its "High Impact," which is the maximum impact for the criteria.
Nudity, meanwhile, apparently had no impact, according to the ACB.
It is quite strange to see the sudden change in Grand Theft Auto III's rating. With a Grand Theft Auto VI apparently coming our way, Rockstar may be gearing up in some way. A remake would seem unlikely given Rockstar's attention to Red Dead Online and rumors related to Bully 2 and Grand Theft Auto VI. Alternatively, they might release the beloved title on something like the Nintendo Switch. However, they have typically strayed from releasing the mainline Grand Theft Auto games on Nintendo consoles, with the exception of Grand Theft Auto: Chinatown Wars for Nintendo DS.
Grand Theft Auto III is a very beloved game and changed the trajectory of the series thereafter. Up until its release, GTA games had a top-down perspective and were considerably less engaging, though GTA III truly revolutionized the series and the gaming industry in ways never thought possible. You can get it now on PlayStation 4, PC, mobile devices, and consoles from generations ago if you can find it for a good price at a thrift store.