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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