difference in size of winscp exe file between 3.3 and 3.4

I've installed 3.3 properly.
Now I just downloaded the application of 3.4. I see a major change in size between them. Why?

2,908,160 WinSCP3.old.exe
819,200 winscp340.exe

I suppose the the old file was installed with setup application, but new file was downloaded directly. The EXE file for direct download is compressed with UPX runtime compression. It is stated on Download page.