I have received the notification about CloudShell's upcoming migration.
Hello,
AWS CloudShell's compute environment, which is currently based on Amazon Linux 2 (AL2), is scheduled to begin migration to Amazon Linux 2023 (AL2023) starting December 4, 2023. The migration will be performed on a Region by Region basis and will be completed by December 14, 2023. There will be no down time as a result of this migration.
For more information on how to prepare for the migration, please refer to the AWS CloudShell User Guide [1].
What should I do and is Linux 2 used on all our g instances?
Agreed. Nothing to do on your side and no impact for the instances that you manage.