Added requirement for PHP4b2.

INSTALL

@@ -20,6 +20,11 @@ Table of Contents:
   to run as CGI under Apache. How you end up doing this is up to you
   (your mileage may vary).
 
+  NOTE: The new plugin architecture required the use of some functions 
+  which are not in all versions of PHP4. You will need at least 
+  PHP4 beta2. If you need to upgrade please go ahead and install the
+  latest release version of PHP4.
+
 a. Obtaining and compiling PHP4
 
   Point your favorite webserver at http://www.php.net/version4/ and

UPGRADE

@@ -5,6 +5,9 @@ guide to make the transition a bit smoother.  If you have been using a previous
 version (0.1 or 0.2), it is suggested that you just start from scratch and 
 configure your settings as if it was your first install.
 
+NOTE: The new plugin architecture required the use of some functions which are
+not in all versions of PHP4. You will need at least PHP4 beta2. If you need to
+upgrade please go ahead and install the latest release version of PHP4.
 
 1.  Backups
 ===========