>> At first, you have to download cod4 patch v1.6 to install patch v1.7.
>> Copy below link & paste to address bar to download cod4 patch v1.6,
>> Then install it to the location of cod4 installation files in your hard drive.
>> After that, download cod4 patch v1.7 by copying the link from below,
>> After that, same process will be applicable for installation.
>> Finally, you will be able to play cod4 in Garena.
N.B. Updated maps are included in cod4 patch v1.7.
Follow the below link to know how to play COD4 in Garena,