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meetdilip Posted the link to each release to upgrade to each subsequent version.
However, you may have issue as they ended up becoming a general "composer update".
My advice would be to get to a composer version, run composer update and complete the instructed database upgrade (hoping for the best). If that doesn't work, looking for the instructions and methodically following them.
I would heavily recommend making reliable backups of the database every step of the way while you do this.
Feel free to visit this thread for a "Flarum Export / Import" feature and comment. It may be a method of making upgrades more "safe" or easier to manage.
https://discuss.flarum.org/d/631-flarum-export-import
Edit: I also locked the other thread in favor of continuing it here. If you run into additional problems directly related to this issue, please post them here instead of branching into new threads