I downloaded the new firmware from here https://www.tp-link.com/us/support/download/tl-wr841n/#Firmware . and I couldn't find any info regarding downgrading to the previous version. can you tell me...

how can I downgrade to the stock firmware version of TL WR841N, hardware version v14.1? after upgrading to new firmware version 0.9.1 4.18 v0348.0 Build 210203 Rel.37242n, coverage area of my router...