When you open version 5, a window will pop up with your support status.
Then there are 2 cases possible:
1/ Your support and maintenance pack is up to date and you just have to double-click on the link to download MUSIC v6.
2/ Your support and maintenance pack is not up to date. In that case, please call eWater at 1300 538 291.
The current version is MUSIC 6.1.0