If you want to upgrade to 6.0 version, you will need to:
1. Upgrade to 5.5 version
2. Upgrade to 5.5 R2 version
3. Upgrade to 6.0 version
Therefore you cannot upgrade directly from 5.0 to 6.0. Upgrade packages are available here
It depends on your decision if you would like to go through all three upgrades at once or to do the first two now and the last one on September (the 6.0 should be released in September).