Maybe a bit late, but I am using a batch to rename the PHP folders (a slightly modified version of the phpswitch I found years ago).
You copy the different folders into your XAMPP installation. Each PHP folder (except for the active one) receives the version number as a suffix (eg. php_5.6.32). In ALL PHP folders, a file (PHP_VERSION) is created, which contains only the respective version number, so the Script can grab this information. But that's all described in the README.
Since PHP7 the httpd-xampp.conf loads the php7ts.dll instead of the php5ts.dll. So i had to extend the script (PHPSwitch.php) to rename these config-files too by following the same approach.
$renameCur = new PHPSwitch_Rename($currInst['path'], $this->_cfg['phpInstallationsPath'] . $this->_cfg['phpDirName'] . '_' . $currInst['version']);
$renameNew = new PHPSwitch_Rename($newInst['path'], $this->_cfg['phpInstallationsPath'] . $this->_cfg['phpDirName']);
$apache_curent = $this->_cfg["phpInstallationsPath"]."apache/conf/extra/httpd-xampp.conf";
$apache_curent_rename = $this->_cfg["phpInstallationsPath"]."apache/conf/extra/httpd-xampp_".$currInst['version'].".conf";
$apache_new = $this->_cfg["phpInstallationsPath"]."apache/conf/extra/httpd-xampp_".$newInst['version'].".conf";
$apache_new_rename = $this->_cfg["phpInstallationsPath"]."apache/conf/extra/httpd-xampp.conf";
$renameCur_apache_conf = new PHPSwitch_Rename($apache_curent, $apache_curent_rename);
$renameNew_apache_conf = new PHPSwitch_Rename($apache_new, $apache_new_rename);
$transaction = new PHPSwitch_Rename_Transaction();
$transaction->add($renameCur);
$transaction->add($renameNew);
$transaction->add($renameCur_apache_conf);
$transaction->add($renameNew_apache_conf);