AOL Instant Messenger -- better known as AIM, and once a staple of the online world -- will close down on Dec. 15 this year, according to Verizon's Oath, which controls the AOL brand.
Oath announced the deadline via official posts on Twitter and Tumblr. No replacement is planned, and the company didn't mention any archival or transition efforts.
AIM originally launched as a Windows app in 1997, and helped to codify much of the lingo and design language around online messaging, even becoming a staple of pop culture. For Mac and iOS users it eventually became accessible through various first- and third-party clients, among them Apple's iChat and Messages. This broad support made it a useful way for Mac and Windows users to communicate with each other.
In recent years, however, it has been eclipsed by other multi-platform messaging services, such as WhatsApp, Slack, Google, and Facebook Messenger. Official AIM clients are still available to download, but haven't been updated in years.
In September, Apple removed AIM support from the High Sierra version of Messages, likely reflecting AIM's decline and the company's awareness of an impending shutdown.