Steps to run multiple PHP version parallelly in single web server.

    Download new PHP version

1. To use diffrent version Download your choice of PHP version (non thread safe) from PHP.net
2. Extract the PHP folder and place it under C:\Program Files (x86)\PHP so that you will have different PHP versions in their own folders.
   
    

    Register new PHP version in IIS

1. Open Internet Information Service Manager ( Start >> Run >> type inetmgr and hit enter).
2. From the Connections pane select the server name (or specific website name). Under Features view, locate and double click PHP Manager.
   
   
    
3. Under PHP Setup, click on Register new PHP version link. Browse the PHP folder up to php-cgi.exe file and click on Open.example,(C:\Program Files\PHP\ php-cgi.exe).
   
   

      Change new PHP version for a website in IIS

1. Open Internet Information Service Manager ( Start >> Run >> type inetmgr and hit enter).
2. From the Connections pane, expand the Sites and select your choice of website. Under Features view, locate and double click PHP Manager.
3. Under PHP Setup, click on Change PHP version link. Select the PHP version from drown down and click OK.
   
   
    
4. To verify if your website is using new PHP version, click on Check phpinfo() link.