To null out repeating error filling server log in build 262.
{Error: Warning: Sound length queried for sound that doesn't exist: /combat/upgrades/alien_lvl_up
Error: Warning: Sound length queried for sound that doesn't exist: /combat/upgrades/marine_lvl_up}
//Fix
►output/lua/combat_Player.lua line 406 add "if xp ~= nil then" without quotes.
►output/sound/ add missing combat.soundinfo file