To Jonix - you've not seen the Mpro or Hermes dev plan so I think it is rather rash to claim that Mpro is lagging behind Thunderbird. Right now, I can only think of 3 areas that thunderbird has going for it, one of which is html emails. The other two have already been sorted to varying degrees in internal releases of Mpro. I can also think of a lot of stuff the Mpro family can do that Thunderbird can't.
Sorry to jump on you, but there's a strange conception that somehow all the ported stuff is better thn anything RISC OS can do for itself. This seems a rather defeatest attitude to me.