The ASCII case insensitivity filesystem feature only works correctly
on systems that have been coerced into using ISO 8859-1, and it does
not work on extended attributes. The kernel has no visibility into
the locale settings in userspace, so it corrupts UTF-8 names.
Enabling this feature makes XFS vulnerable to mixed case sensitivity
attacks. Because of this, the feature is deprecated. All users
should upgrade by backing up their files, reformatting, and restoring
from the backup.

Administrators and users can detect such a filesystem by running
xfs_info against a filesystem mountpoint and checking for a string
beginning with "ascii-ci=". If the string "ascii-ci=1" is found, the
filesystem is a case-insensitive filesystem. If no such string is
found, please upgrade xfsprogs to the latest version and try again.

This option will become default N in September 2025. Support for the
feature will be removed entirely in September 2030. Distributors
can say N here to withdraw support earlier.

To continue supporting case-insensitivity (ascii-ci=1), say Y.
To close off an attack surface, say N.