The following instructions describe the process of installing both PHP 4.x and PHP 5.x in CGI mode on the same server:

1. Unpack PHP 4 distributive to "c:\php4" folder.

2. Unpack PHP 5 distributive to "c:\php5" folder.

3. Set "Read" NTFS permissions for "WSPWebUsers" group (or orther specified on WEB service properties page in WSP) on both "c:\php4" and "c:\php5" folders.

4. Rename "c:\php4\php.ini-recommended" to "c:\php4\php.ini".

5. Open "c:\php4\php.ini" for editing and change the following settings:

cgi.force_redirect = 0

extension_dir = "c:\php4\extensions\" 

6. Save "c:\php4\php.ini" and close.

7. Rename "c:\php5\php.ini-recommended" to "c:\php5\php-cgi-fcgi.ini".

8. Open "c:\php5\php-cgi-fcgi.ini" for editing and change the following settings:

short_open_tag = On

cgi.force_redirect = 0

extension_dir = "c:\php5\ext\" 

9. Save "c:\php5\php-cgi-fcgi.ini" and close.

10. In IIS manager under "Web Service Extensions" node add two new web extensions:

"PHP 4" with required file "c:\php4\php.exe"

and

"PHP 5" with required file "c:\php5\php-cgi.exe"

11. Set both extensions status to "allowed".

12. If you have previously installed PHP 4 or PHP 5, please, make sure you don't have a) any PHP libraries in "c:\windows\system32", b) php.ini in "c:\windows" and c) paths to PHP folders in PATH system variable.