First check your current php version using xampp dashboard.
Now follow these step to get rid of update version of php.
Remember,It will be work for any released update,if you can follow all approach correctly.
Step 1: Download official xampp release from sourceforge and extract zip file on your hard drive.
Step 2: Then go to your installed xampp drive.On my case it is in D drive and make sure you created previous backup by raname php to php5 and apache to apache5.
Step 3: Now open up your downloaded file.On my case it is in F drive and just copy php and apache folder to your main xampp directory.
Step 4: Copy the address location of installed xampp directory also open php.ini from php folder to locate directory.I found 8 place to replace.