Back in 2020, Minecraft developer Mojang announced that players of the Minecraft Java Edition would need to migrate their old Mojang accounts to Microsoft accounts if they wanted to keep playing that version of the sandbox game. Originally, Mojang thought it would have a 2021 deadline for all players to make that move, but as it turns out, the studio gave Java Edition players a lot more time.
However, a new blog post from Mojang has revealed that time is finally running out for Mojang accounts to move to Microsoft accounts. It announced that the absolute final day to transfer those accounts will be September 19 at 11 am Eastern time. If the Mojang account doesn't transfer to the Microsoft account after that day and time, users won't be able to play Minecraft Java Edition anymore. Also, September 5 will be the last day the studio will be able to assist any Mojang account holders with migration-themed support tickets.
The good news is that Mojang has a Java Edition FAQ to make moving accounts easier. The better news is that after switching to Microsoft accounts, users can also play the Minecraft Bedrock Edition on Windows for free, and can also claim an in-game cape.