the current version is 1.2.3 (but you can getaway with installing 1.2.2 and no more , simply because the 1.2.3 patch is map fixes and a new map) if u have 1.2 installed , then install all patches in order , 1.2.1 , 1.2.2 & 1.2.3 , you cand find these at esf-world and half-life files , or to make life a little easier , you can go get the 1.2.3 full installer