To update KKManager itself, download the latest release and overwrite the old files in your [UTILITY] KKManager folder.
If you own the Steam version ( Koikatsu Party ), disable auto-updates in Steam. Official Steam updates can break community mods, requiring you to re-apply the HF Patch to fix them. koikatsu partyrepack upd
Most modern repacks (like BetterRepack) include a standalone launcher with an "Update" button . To update KKManager itself, download the latest release