Yes - there are some custom RPM's around to take you to 4.0.14. The problem with 4.0.x is that it will not just drop into Plesk without some hacking. As of 4.0.x they've added a new restricted word, called "ssl".
The modified RPM's get round this and ensure that things like Horde (webmail) do not break.
This should actually work on verion 5 as well - although I haven't tried.
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