Minecraft: Java Edition is migrating all Mojang Accounts to Microsoft Accounts

Minecraft: Java Edition has historically used their own Mojang Accounts for access and saving, but now Mojang Studios is planning to migrate all current and future Mojang Accounts to

MCL-19637] Migrated Microsoft Account at Demo Mode - Jira

Can't play Minecraft after migrating Mojang account - Microsoft Community

Microsoft Account Migration FAQ

Minecraft Java Edition will require a Microsoft account starting next year

3 Ways to Create a Minecraft Account - wikiHow

Minecraft: Java Edition locks out old accounts in March

Minecraft Account Migration Deadline Set for March 2022

Microsoft Account Privacy Settings

Minecraft Java Edition players must move to Microsoft accounts by September 19 - Neowin

Account migration last call

Migration, Minecraft Wiki

You might lose your Minecraft account unless you act now