How can I store videos of events for longer than 6 months?
To keep the video related to a camera event for longer than 3 months, it's recommended that you link a Dropbox account to your camera or connect to an FTP storage space. The videos are then saved on this storage space and are not erased by the maximum event storage time setting.
You can find more information about Dropbox in this article. Likewise, you can find more information about FTP storage here.