Which postgresql should i choose to migrate from 8.3 ? 8.4 or 9.1?

Hi!
We are using postgresql 8.3 in my work, and the need to migrate to a
newer version became urgent :)

I've been reading the release notes for versions 8.4 and 9.1, but is not
clear to me which problems I can have with version 8.4 or 9.1 from a
dump 8.3

My boss thinks we would have fewer problems if we use the version 8.4, I
believe that it is best to have version 9.1, and the number of problems
will be the same as in version 8.4

In favor of version 9.1 is that it will be supported until 2016.

What is the structural difference or what was the reason to have a
version 9 and version 8?

Please, could you help to give peace of mind to my boss and make sure
that the version we choose to be as smooth as possible compatible with
version 8.3?

indeed to restore the dump of the 83 in 9.1 had a bug in UTF-8, will I
have the same problem with the 8.4???

What will be the problems you have had to migrate from version 8.x to
the 8.4 or 9.1???

is it a good idea migrate to 9.1 rather than 8.4?

Perhaps, it would be a good idea to have a page on the postgresql site
which is titled: How to convince my boss to install latest version. ;)

Farewell, and thank you for your help.

Regards.
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