Version 6 is a big step up from version 5, yes. Have a look at the release documentation for details.
I'm not sure what you mean about the IP blacklist but I dont think there's anything in Zimbra that would do it, it sounds like something that iptables could take care of though.
If there's not a build for your current server anymore then the best way to migrate is to build a replacement server that supports your current and destination build. So for example, build a ubuntu server and install Zimbra 5.0.13 onto it then migrate your installation over to that and then upgrade it to v6. This has been documented a few times on the forums, and there are other ways to do it too. |