+ * There is now support for copy-on-write substrings and
+ mutation-sharing substrings.
+
+ * A new family of functions for converting between C values and
+ Scheme values has been added that is future-proof and thread-safe.
+
+ * The INUM macros like SCM_MAKINUM have been deprecated.
+
+ * The macros SCM_STRINGP, SCM_STRING_CHARS, SCM_STRING_LENGTH,
+ SCM_SYMBOL_CHARS, and SCM_SYMBOL_LENGTH have been deprecated.
+
+ * There is a new way to deal with non-local exits and re-entries in
+ C code, which is nicer than scm_internal_dynamic_wind.
+
+ * There are new malloc-like functions that work better than
+ scm_must_malloc, etc.
+