+* Version specific information
+
+** For Emacs 18 users: "old byte-compiler" vs "new byte-compiler"
+
+In this package, we use compile-time evaluation heavily.
+Unfortunately, the byte-compiler bundled with Emacs 18 (the "old
+byte-compiler") does not have features such as `eval-when-compile'
+and `eval-and-compile', and our emulation version of these macros
+evaluate "compile-time evaluation" at load-time or at run-time!
+In addition, the "old byte-compiler" cannot compile top-level use of
+macros and leaves most of our code uncompiled.
+
+Therefore, we recommend you to use the "new" optimizing byte-compiler.
+It is the origin of byte-compiler bundled with Emacs 19 and later.
+
+Optimizing byte-compiler for Emacs 18 is available from the Emacs
+Lisp Archive and its mirrors.
+
+In Mule 1.* days, "contrib" package for Mule 1.* was distributed and
+it contained the "new byte-compiler" for Mule. But, I think it is
+difficult to obtain this package now.
+
+AFAIK, the "new byte-compiler" for Emacs 18 is also bundled with SKK
+9.6 or SKK 10.62a. You can get SKK 10.62a from the following URL;
+
+ http://openlab.ring.gr.jp/skk/maintrunk
+
+They include patch for Mule 1.*.
+
+
+** For Emacs 19.34 and XEmacs 19.14 users: "old custom" vs "new custom"
+
+"custom" library bundled with Emacs 19.32 - 19.34, XEmacs 19.14, and
+Gnus 5.2/5.3 is "old", its API is incompatible with "new custom"
+bundled with Emacs 20.1, XEmacs 19.15, or newer, and Gnus 5.4/5.5.
+
+"new custom" for Emacs 19.34 and XEmacs 19.15 - 20.2 is available
+from the following URL.
+
+ftp://ftp.dina.kvl.dk/pub/Staff/Per.Abrahamsen/custom/custom-1.9962.tar.gz
+
+(Note that "new custom" bundled with XEmacs 19.15 - 20.2, and Gnus
+5.4/5.5 is older than this version.)
+
+Before installing "new custom", you should check the following points.
+
+ 1) If you stick to Gnus 5.2/5.3 (or any other applications which
+ use "old custom"), you should not install "new custom".
+
+ 2) If you use Mule (based on Emacs 19), you must apply this patch
+ to "new custom".