Strum GS-2 Acoustic + Electric Upgrade from Strum GS-2 Session
http://www.pluginboutique.com/product/1-Instruments/4-Synth/2524-Strum-GS-2-Acoustic-Electric-Upgrade-from-Strum-GS-2-Session
Please Note: This is an Upgrade for Users of Strum GS-2 Session
 
Platinum has Strum Session 2 This upgrade will work?
 
Regards
Snehankur
 

IDK but this https://shop.cakewalk.com/1244/catalog/catalog.1307/category.60182/product.161667/ at the CW store is and is currently on sale for a little less than the link posted above.

It's $49 to upgrade at Applied Acoustics Systems - the maker of the plug-in. 
I have Sonar Platinum and it includes GS-2 Strum Session, so I went to get the upgrade but it needs the serial number and I cannot determine how you get the serial number for this product.   Cakewalk provides serial numbers for most of the other add-ons.  Where is this serial number found?

From memory the Strum Session 2 supplied with Platinum is the "SONAR" version. It probably does not work in other hosts. As such there isn't a serial number (check your account: https://www.cakewalk.com/My-Account/Products) so this isn't a valid upgrade path.
 
Cakewalk have their own upgrade option on their store: "Please note: Special upgrade prices are offered to SONAR Platinum and SONAR X3 Producer customers using AAS Strum Session (SONAR Edition). Please be sure you are logged into your Cakewalk account to see the correct pricing."