7.9 on qnap ts-119

hello
i'm on 7.2.2 on qnap ts-119 (i could install it also on ts-269). official qnap support is for 7.7.2, how to install 7.9 without risks and easily (i'm not available to get crazy with linux commanbds please)?

i read somewher there could be some issue about folder position, is it true?