Thank you for your help.

I have just do

composer require archlinux-de/flarum-import-fluxbb

I have no idea of how enabled the extension. Can you tell me what kind/subject of guide/tuto i have to refer ?

    GildDart within the administration area you need to enable extensions after installation.

      I finally understood that it was installing an extension in the BO ... and then i continued with migratetoflarum/old-passwords. And i get a lot of red flat in my terminal.

      In fact I wanted to see the feasibility of migrating a forum for a customer. You are right llaumgui i will certainly need help.

        24 days later
        a month later

        Dear @all and @llaumgui .
        I am an old Administrator/Moderator of https://www.fedoraonline.it (The Italian Fedora Forum). @llaumgui you help us (me and Robyduck) a lot of years ago to update our website (to fluxbb). I leave fedoraonline.it time ago for personal reason (new job, no time, etc.) but I continue to study php and website.
        And I create a new motorbike community (https://www.theroyals.it) based on fluxbb over 10 years ago.

        Now I need to migrate to flarum. I have over 5k users, over 230k posts . So I decide to update the importer of archlinux-de community (also to understand better the flarum coding).
        I fork the project here: https://github.com/marionline/flarum-import-fluxbb

        I update something (example I use fluxbb config to connect to fluxbb database and import it) and fix some errors I encountered. The work is not finished yet.

        I have a question that I don't understand how to resolve. I am updating the posts import process.
        It is managed by the src/Importer/Posts.php file.
        It is strange because if I don't remove that line (line 261 more or less):

        261   $formatter->addConfigurationCallback(ContainerUtil::wrapCallback(ConfigureMentions::class, $this->container));

        I have this issue:

        PHP Fatal error:  Uncaught TypeError: Flarum\Mentions\ConfigureMentions::addUserId(): Argument #2 ($mentions) must be of type array, null given in /forum/vendor/flarum/mentions/src/ConfigureMentions.php:96

        If I remove the line no error. Why?
        I try also to flush() the formatter in convertPostContent() function but after some conversion (near 35, I don't know why at 35 and not 25 or 100 posts) same error above.

        Any suggestions are appreciated. Thank you!

        a month later

        Dear all. I update the fluxbb-to-flarum extension for my purpose.
        I add the db table prefix support so it should resolve this issues.
        It is not too much personalise, so it could be use for a general migration process from fluxbb to flarum.

        I suggest to make a migration locally or on a personal server, not on a share hosting. I migrate my old fluxbb forum with over 5k users and over 230k posts and it take near 1hours on my old laptop.

        Hope it can help other people.

        Thank you!

          8 months later

          So are there any working and supported plugins to migrate FluxBB to Flarum?

            5 days later
            3 months later

            Finally got round to looking at this, and its fallen over right at the start. It doesn't handle that your flarum tables might have a table prefix .

            My fluxBB install is in another database and those tables have a prefix and the code just makes a complete mess of these.

            So it looks like I'm going to have to hack all the code around to get the importer to work.