Bandai Namco announced that service for Sword Art Online: Memory Defrag will end on August 30, 2021. The message is fairly brief, only stating when end of service will begin and when paid currency can no longer be used in game. As it stands, there are currently no plans for an offline version. [Thanks, 4Gamer!]
As of July 1, 2021, players using the global client can no longer purchase paid currency in Sword Art Online: Memory Defrag. However, players can use any paid currency they currently have until end of service. The stipulations are slightly different for players using the Japanese client. Players will have access to purchase paid currency until July 30, 2021. Similar to the Global client, the paid currency can be used until Sword Art Online: Memory Defrag goes offline.
The statement also mentioned that the end of service date for Sword Art Online: Memory Defrag may be subject to change. As it stands, the definite date remains August 30, 2021. This includes both the Japanese and global versions.
Several collaboration events appeared in Sword Art Online: Memory Defrag since its release. These included a Persona 5 collaboration. For a limited time players could obtain Joker, Panther, and Skull.
Sword Art Online: Memory Defrag is immediately available for Android and iOS devices. Its end of service is scheduled for August 30, 2021.