How do I change the used PHP version? I am using Drush to update modules.
When I run the command php -v it correctly shows I am running version 5.5

I then use the command drush rf followed by drush up to perform any updates.

I am using the Schema.org Metatag module which requires php version 5.
The website is running php version 5.5.37

The default CLI version on Hostgator shared server is 5.4.45.
That is what I was originally using for drush. When I received the message below I found the path to use php 5.5 but I am still getting the same message.
So I can't figure out how it still sees php ver 5.4.45 and how to resolve this so it doesn't keep disabling that module.

When Drush runs an update I get the following message:
Schema.org Metatag requires at least PHP 5.5. (Currently using PHP   [warning]
5.4.45)

And then it disables the Schema Metatag module.

NOTE:
When I run command drush status:
PHP configuration: opt/php55/lib/php.ini
Drush version is 8.1.11

Thanks

Extra information

.bash_profile

PATH=$PATH:$HOME/bin 
export PATH 
alias composer="/opt/php55/bin/php ~/bin/composer.phar" 
alias drush="/opt/php55/bin/php ~/.composer/vendor/bin/drush.php" 


.bashrc

 alias php='/opt/php55/bin/php' 
 alias composer='/opt/php55/bin/php ~/bin/composer'
 export DRUSH_PHP='/opt/php55/bin/php' 



php -v returns PHP 5.5.37 
which php doesn't return anything 
drush status returns PHP configuration /opt/php55/lib/php.ini 


But, when I use Drush to update a module I still get: Schema.org Metatag requires at least PHP 5.5. (Currently using PHP [warning] 5.4.45)
Find the path to php 5.5’s binary. 
Find the path to drush.


Execute 

/path/to/php_55/bin/php /path/to/drush status