php version change wont reflect

Hi I have an old app that requires php 7.3 which i have still installed I added a subdomain under a main domain that runs v8.1 I changed the subdomain to 7.3 SHELL : php -v shows 7 ( in the folder of the subdomain) phpinfo(), now shows 7 if i run it as subdomain/info.php if i run it like domain/folder/info.php shows 8 But anyway the APp itself is reading version as 8 and throwing errors ! What could be the possible reasons ? htaccess seems correct and i restarted php and apache ... ideas?