Long answer: it is possible!

1. Temporarily rename existing xampp folder
2. Install xampp 1.7.7 into xampp folder name
3. Folder containing just installed 1.7.7 distribution rename to different name and previously existing xampp folder rename back just to xampp.
4. In xampp folder rename php and apache folders to different names (I propose php_prev and apache_prev) so you can after switch back to them by renaming them back.
5. Copy apache and php folders from folder with xampp 1.7.7 into xampp directory

6. In xampp directory comment line apache/conf/httpd.conf:458

   #Include "conf/extra/httpd-perl.conf"

7. In xampp directory do next replaces in files:

php/pci.bat:15

from

"C:\xampp\php\.\php.exe" -f "\xampp\php\pci" -- %*

to

set XAMPPPHPDIR=C:\xampp\php "%XAMPPPHPDIR%\php.exe" -f "%XAMPPPHPDIR%\pci" -- %*

php/pciconf.bat:15

from

"C:\xampp\php\.\php.exe" -f "\xampp\php\pciconf" -- %*

to

set XAMPPPHPDIR=C:\xampp\php "%XAMPPPHPDIR%\.\php.exe" -f "%XAMPPPHPDIR%\pciconf" -- %*

php/pear.bat:33

from

IF "%PHP_PEAR_PHP_BIN%"=="" SET "PHP_PEAR_PHP_BIN=C:\xampp\php\.\php.exe"

to

IF "%PHP_PEAR_PHP_BIN%"=="" SET "PHP_PEAR_PHP_BIN=C:\xampp\php\php.exe"

php/peardev.bat:33

from

IF "%PHP_PEAR_PHP_BIN%"=="" SET "PHP_PEAR_PHP_BIN=C:\xampp\php\.\php.exe"

to

IF "%PHP_PEAR_PHP_BIN%"=="" SET "PHP_PEAR_PHP_BIN=C:\xampp\php\php.exe"

php/pecl.bat:32

from

IF "%PHP_PEAR_BIN_DIR%"=="" SET "PHP_PEAR_BIN_DIR=C:\xampp\php" IF "%PHP_PEAR_PHP_BIN%"=="" SET "PHP_PEAR_PHP_BIN=C:\xampp\php\.\php.exe"

to

IF "%PHP_PEAR_BIN_DIR%"=="" SET "PHP_PEAR_BIN_DIR=C:\xampp\php\" IF "%PHP_PEAR_PHP_BIN%"=="" SET "PHP_PEAR_PHP_BIN=C:\xampp\php\php.exe"

php/phar.phar.bat:1

from

%~dp0php.exe %~dp0pharcommand.phar %*

to

"%~dp0php.exe" "%~dp0pharcommand.phar" %*

Enjoy new XAMPP with PHP 5.3

Checked by myself in XAMPP 5.6.31, 7.0.15 & 7.1.1 with XAMPP Control Panel v3.2.2

If you want to downgrade php from 7.1.1 to 5.6 in xampp follow the steps(For Windows):-

1. Go to https://sourceforge.net/projects/xampp/files/XAMPP%20Windows/5.6.36/
2. Download and extract the file xampp-win32-5.6.36-0-VC11.zip see the image [image 1][1]

3. Delete php folder and apache folder present in C:\xampp

4. Copy php folder and apache folder from extracted file and paste it to C:\xampp

5. Add " C: " before \xampp\ to php ini file present in php folder.

6. Start your apache and MySQL and check php version. It will show php 5.6.36

The best method is to change the PHP settings in

/apache/conf/extra/httpd-xampp.conf

to reflect the new version of PHP you want to use

In my case I unpacked PHP5.4 to C:\XAMPPLITE\PHP5.4 and then updated key lines in this file such as:

SetEnv PHPRC "C:\\xampplite\\php5.4"

LoadFile "C:/xampplite/php5.4/php5ts.dll"

PHPINIDir "C:/xampplite/php5.4"

You also need to ensure that the correct version of php5apache2_2.dll is installed

To ensure this I copied the new version of php5apache2_2.dll to the Apache modules directory with a unique name, and then modified the configuration to match that:

copy php5.4\php5apache2_2.dll apache\modules\php5apache2_2-5_4.dll

and in the httpd-xampp.conf file

LoadModule php5_module modules/php5apache2_2-5_4.dll