Requires redis 4.3.4

error while installing. how to fix this?

it seems you’re using frappe from develop branch and trying to install ERPNext from version-14 branch.

try same branch for both apps.

how to determine? what should i do?

follow the documentation carefully it doesn’t confuse the branches

the first bench is setup on version-14 frappe

your screenshot warning mentions frappe 15.0.0.dev0 and you are trying to get app ERPNext on version-14 branch.