To upgrade version 2.0 or 2.01 to 2.1 download the zip. Unzip the files, and copy the DroxUI folder to your shells folder.
<Vangaurd install folder>\VGUIAssets\Shells\
You should get warnings to overwrite files, say yes to all. There were changes to the index.xml that need to be included, so if you have changes in yours back it up or use the backup that the setup program creates to add your changes back in.
If you do not get the overwrite warnings then either you do not have DroxUI installed or you are copying to the wrong folder.
Setup now reads your current settings, and I fixed the hotbar graphics for the small and large hotbars. This update includes also the 2.0.1 updates. No need to install 2.0.1 also.
I do recommend for a clean install to just delete DroxUI and download the new version, but for some that may be too much drama.