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Besides these caveats we've not encountered any major problems with upgrades in our lab tests (tested on CentOS/RedHat 6, Debian 7, Ubuntu 14).
We recommend using MongoDB 2.4. MongoDB 2.6 is currently not covered by our installation and configuration guides as it has a somewhat different authorization infrastructure. The setup instructions below may fail with late versions of MongoDB 2.6.
As of September 2015 the installation instructions below are no longer applicable; the installer will take care of installation and initial configuration of MongoDB for you.
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