-* <visitors>
-* <new-style printing>
-* <noncommutative symbols>
-* Improved the speed of subs() and normal() by the use of maps instead of
- lists.
+* Added support for (acyclic) visitors, to allow cleaner implementations of
+ algebraic algorithms.
+* <iterators>
+* Completely revamped the implementation of expression output. It is now
+ possible to add new output formats, to change the behavior of predefined
+ formats at run-time, and to have different output styles for algebraic
+ functions.
+* Symbols can be made non-commutative.
+* Improved the speed of subs(), normal(), to_rational() and to_polynomial()
+ by the use of maps instead of lists. The old forms
+ subs(const lst & ls, const lst & lr, unsigned options)
+ to_rational/to_polynomial(lst & repl)
+ are still available for compatibility, but using the new forms
+ subs(const exmap & m, unsigned options)
+ to_rational/to_polynomial(exmap & repl)
+ is more efficient, especially when the number of replacements is large.