WSE 2.0 SP3 has just been released on MSDN  here. There are no additional new features just stress, perf and security fixes plus some other less significant fixes. Typically just the last two SPs are left on the download site, but we have decided to keep WSE 2.0 SP1 available for another 6 months to ease transistion to later versions. Although not stated in the readme, SP3 does not have to have .NET 1.1 installed, ie. it will install with just .NET v2.0 on the machine, but this is unsupported given that .NET v2.0 is months away from shipping.