[Setup] middle migration steps from 2.5.4-r2 to 3.3.1

[Giuliano Castelli]

Dear all,

for upgrading from Plone 2.5.4-r2 to 3.3.1 what are
the middle steps?

I have to go from 2.5.4-r2 to 2.5.5 and then to 3.3.1;
or from 2.5.4-r2 to 3.0.6 and then to 3.3.1; or even perhaps
from 2.5.4-r2 to 2.5.5, then from 2.5.5 to 3.0.6, and
finally to 3.0.6 to 3.3.1? Or through some other path?

Any help appreciated.

thanks in advance,
Giuliano.