FN-2021-461 Rack mount (2 post) issue on Universal 5520 Models has been released. You can find the full field notice here: https://extremeportal.force.com/ExtrArticleDetail?an=000095883&q=FN-2021-461
XN-2P-RMKIT-005 (2 post rackmount kit) can only be used with 5520 models that are revision AD or higher. Additional screw holes are included in revision AD and above, which allow the XN-2P-RMKIT-005 (2 post rack mount kit) to be used with 5520 models.
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