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Solution 1:

Note: Popper is not longer developed. The last working version is for 12.04. Later releases are not supported.

You may want to have a look a Popper, a nice and actively developed project by @RalfHersel.

Solution 2:

Popper

I would suggest popper as a good replacement as it can deal with POP & IMAP and multiple accounts popper is not in the Software Center you need to install it from a .deb package with can be downloded from there launchpad page here

Hope this helps