[Evolution] plugin remove duplicated mail not visible

["J.L. Blom" <jlblom neuroweave nl>]

Hi,
I have the plugin "remove duplicated mails" in my plugin Manager.
However, I cannot find anywhere how to activate it: no item is found in
any drop-down menu.
I have an old (but very stable) version (2.6.3) (and it functions
correctly so why change a winning horse and get the hassle to have all
old mail transferred for free).
I get however regularly duplicate mail especially from maillists and
would like to remove them automatically.
Has anybody a solution (short of upgrading)?.
Thanks
Joep