Upgrade to Unwired Platform version 2.0 by running the installer where version 1.5.5 is installed, overwriting that installation.
It is no longer necessary to uninstall the previous version of Unwired Platform before upgrading, or to install the upgrade version in a different location. After performing a full system backup of the host where version 1.5.5 is installed, simply run the installer for version 2.0 on that system.