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As of September 2015 we recommend version 3.0 of MongoDB. The installer in our most recent product releases offers to install that version of MongoDB for you if none is present on your server, and no manual configuration is required. You can definitely continue to use MongoDB 2.4 or 2.6, but 3.0 brings in a number of important performance improvements.
See Please see our Product Compatibility page for details regarding what product releases work (best) with which MongoDB versions. Some products support the compatibility configuration option db_use_v26_features, but that generally comes at the price of reduced efficiency and robustness.
Upgrades
For upgrading an existing MongoDB installation we HIGHLY RECOMMEND that you follow the official documentation for MongoDB upgrades - the two most critical aspects are
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