Can I upgrade one ports to ver 7.0 without affecting the other installations
The installer will only upgrade the agents for the specified port - ie when the installer is run and the "upgrade -> multitier -> collector | middleware" option is selected, the next question the installer asks is what port the agent is running on. This will allow the user to upgrade a particular installation (collector or middleware) if there are more than one middleware or collector instances on the server but running on different ports.
So if there are two middleware installs on a server and they are installed on different ports (and in different paths) then it would be possible to upgrade one middleware installation but without upgrading the other since they are on different ports and paths. Similarly, if there are two monitored instances on a server but the collectors are running on different port/paths, then it would be possible to upgrade one collector install without upgrading the other - to ugrade the other the user would need to run the same steps but select the other port to upgrade.