Cannot update due to custom paid theme

I have a strange request.

Due to a customized paid theme i cannot upgrade from 1.17.3 to 1.18 because otherwise i will loose all customization.

The guy who made the custom theme isn't responding to my mails anymore, so i don't know if/when i will receive an updated customized 1.18

I was wondering if there is a method to justy apply all patches from 1.17.3 to 1.18 without using the full upgrade package.

I applied patches in the past to 1.17 to solve a couple of bugs.

Thanks

You'd have to upgrade as new code depends on new database patches.

Cheers.

KevinTheJedi Thanks you can close the post.