1.8 Deprecated Language Features

Deprecated language features are not expected to appear in future Common Lisp standards, but are required to be implemented for conformance with this standard; see Required Language Features.

Conforming programs can use deprecated features; however, it is considered good programming style to avoid them. It is permissible for the compiler to produce style warnings about the use of such features at compile time, but there should be no such warnings at program execution time.