Update from 14 with PHP 7.4

Hi all,
I had been lazy updating my NC installation … :frowning: MY fault β†’ sorry for that!
I am running NC 14 and have PHP 7.3 no longer available on my shared hosting. I have to use PHP 7.4. How do I proceed? I learnt that 18 is the next lowest version to support PHP 7.4. Is there any way to directly update from 14 to 18?!?
Thanks so much in advance!

PS: When trying to run the current installation in the browser I get β€œThis version of Nextcloud is not compatible with > PHP 7.3.”