Enquiry regarding PB 12.5.1

I read some documents that PB 12.5.1 will support compilation of PB for 64bit platform. I tried installing the latest PB which is 12.5.2, thinking that it also have this features. Based on the documents, platform dropdown is available in project wherein you can choose either a 32bit or 64bit. But didn't find it. My question, is this feature only applicable for .NET or PB application as well? If yes, where to find that Platform dropdown? Hope someone tried it and can share their insights.

Your answer is highly appreciated.