MS SQL Server sys.indexes vs sys.sysindexes system table difference

For indexes there are 2 system tables: sys.indexes and sys.sysindexes.
I'd like to know what are their differences. Both contain information about indexes then why they are separate?

Thanks in advance.

sys.sysindexes - is old and deprecated.


This SQL Server 2000 system table is included as a view for backward compatibility. We recommend that you use the current SQL Server system views instead.

you should use sys.indexes.

StackExchange Database Administrators Q#213438, answer score: 5