Starting with the the 1.4 release, it is possible to update easily from one version to another.

1. download win-builds-1.5.0.exe and replace the bin/yypkg.exe file from your installation with it;
2. double-click on this file, click on Change Mirror in the upper-left corner and replace 1.4.0 with 1.5.0 in the URI;
3. click on Process to run the update.