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 Section 18.104.22.168 (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.
The functions in Figure 1–2 are deprecated.
#S reader macro forces keyword names into the KEYWORD package; see Section 22.214.171.124 (Sharpsign S). This feature is deprecated; in the future, keyword names will be taken in the package they are read in, so symbols that are actually in the KEYWORD package should be used if that is what is desired.