Below mentioned are the steps to configure PHP in ISAPI mode:
1. Download the PHP4 Zip file in Windows server.
2. Unzip the PHP4 Zip file and install it on the default directory C:\php4
3. Copy the php.ini-recommended and paste it in Windows directory and rename it to php-isapi.ini.
4. Open php-isapi.ini file and search for the below mentioned line:
extension_dir = “./”
5. In the above mentioned line, enter the PHP4 extension directory as mentioned below:
extension_dir = “C:/php4/extensions/”
6. Save the file.
7. Download the PHP5 Zip file in Windows server.
8. Unzip the PHP5 Zip file and install it on the default directory C:\php5.
9. Copy the php.ini-recommended and paste it in Windows directory and rename it to php-cgi-fcgi.ini.
10. Open php-cgi-fcgi.ini file and search for the below mentioned line:
extension_dir = “./”
11. In the above mentioned line, enter the PHP5 extension directory as mentioned below and also disable the force_redirect:
extension_dir = “C:/php5/extensions/”
cgi.force_redirect = 0
12. Save the file.
13. Set C:\php4\sapi\php4isapi.dll to be the “PHP App.Path” in the HELM web service.
14. Set script map to C:\php5\php-cgi.exe. The administrator can set script map using the below mentioned steps:
a. Open HELM home page.
b. Click on HELM extensions.

c. Click on Hex Setup.

d. Click on PHP Versions.

e. Click on Add New and enter as PHP5 and set the script map.

From the above mentioned steps you should be able to switch between the two versions of PHP from HELM control panel.
1. Download the PHP4 Zip file in Windows server.
2. Unzip the PHP4 Zip file and install it on the default directory C:\php4
3. Copy the php.ini-recommended and paste it in Windows directory and rename it to php-isapi.ini.
4. Open php-isapi.ini file and search for the below mentioned line:
extension_dir = “./”
5. In the above mentioned line, enter the PHP4 extension directory as mentioned below:
extension_dir = “C:/php4/extensions/”
6. Save the file.
7. Download the PHP5 Zip file in Windows server.
8. Unzip the PHP5 Zip file and install it on the default directory C:\php5.
9. Copy the php.ini-recommended and paste it in Windows directory and rename it to php-cgi-fcgi.ini.
10. Open php-cgi-fcgi.ini file and search for the below mentioned line:
extension_dir = “./”
11. In the above mentioned line, enter the PHP5 extension directory as mentioned below and also disable the force_redirect:
extension_dir = “C:/php5/extensions/”
cgi.force_redirect = 0
12. Save the file.
13. Set C:\php4\sapi\php4isapi.dll to be the “PHP App.Path” in the HELM web service.
14. Set script map to C:\php5\php-cgi.exe. The administrator can set script map using the below mentioned steps:
a. Open HELM home page.
b. Click on HELM extensions.

c. Click on Hex Setup.

d. Click on PHP Versions.

e. Click on Add New and enter as PHP5 and set the script map.

From the above mentioned steps you should be able to switch between the two versions of PHP from HELM control panel.