OpenAI announced the planned retirement of Custom GPTs on September 11, and its updated migration FAQ now provides a more concrete timeline and migration boundary. The current standard retirement date is scheduled for December 11, 2026; qualifying Enterprise workspaces with an approved deferral can extend that to February 11, 2027. When migration is available, creators can choose “Migrate to plugin” from My GPTs. GPT instructions become a skill in the new plugin, knowledge files are copied into reference files, and connected apps are added to the plugin. However, Custom Actions do not migrate automatically and may need to be rebuilt with an available app or a custom MCP integration. Existing sharing settings do not carry over—the migrated personal plugin starts private—and the GPT’s selected model is not transferred. The original GPT remains usable until retirement but becomes read-only after migration. For users and teams that rely on Custom GPTs, the key impact is the need to move and test workflows before retirement, especially where Custom Actions are involved.