Transfer CB from Joomla2.5 old site to new Joomla4 new site on different server

Since CB is so heavily integrated I am not sure a straight phpmyadmin table export and import will work for such a Joomla version difference. I have tried this with other things and it only locks up J4 making me recover from backup. I saw I a previous post a 3 to 4 on same server is not a problem, I don’t have that luxury unfortunately.
Any advise on process here. IE do I install CB first in 4, then do select table exports and imports, or do the table export/imports then run the install on 4?

Currently my 4 is back to not having CB in it do to a failed attempt. So I can proceed down either path at the moment. Thoughts or experiences would be greatly appreciated as you can image there is lots of needed data in the old 2.5CB install.

CB is tied to Joomla. Specifically the _users table, which is tied to several other tables. It's not as simple as just moving the data over, because your users may now no longer exist or if the move is done incorrectly and user ids are rebuilt then their data is no longer in sync.

I do not suggest going from 2.5 to 4.0. Joomla is not designed to handle that migration. Joomla 3.10 to 4.0 is the official migration path. I suggest migrating to Joomla 3.10 first then your data will be up to date to migrate to 4.0. In fact it'd be best to just directly upgrade to 4.0 then move the data to a fresh install if you wanted to start off fresh. I suggest doing this from a clone of your existing site as well so your existing site is untouched until you're done.

You probably know that already, just for other readers: The upgrade from 2.5 to 4.0 has to be done in 3 steps that are in-place mini-migrations:
- 2.5 to 3.5.1,
- then to 3.10,
- and finally to 4.0,

All Joomla upgrades/mini-migrations planing can start using this official guide:
docs.joomla.org/Special:MyLanguage/Why_Migrate

And in details from 2.5 to 4.0 is in the official documentation here:
docs.joomla.org/Special:MyLanguage/Planning_for_Mini-Migration_-_Joomla_2.5_to_4.x

Of course always **backup** first (and **test backup** restoration on a different server.

Best is to exercise on a site clone taking detailed notes of actions, and once happy, replace original site by new one (or if site is very dynamic, backing up and redoing the migration offline according to notes taken during exercising).

Thanks everyone.
For the main site migration I used CP_Transfer which did a good job of Joomla move direct from 2.5 to 4.0. I was able to move/migrate everything except the Kunena forum which is proving to be and exceptional amount of work.

As for CB, I went back, and since I used CP-Transfer ID's were managed reasonably well, then did the table export and import for _comprofiler and the others. So far the majority of data and linkages are in place. A few oddities, however within a few hours should have it cleaned up.

I would say this site was relatively simple however with only CB, Kunena, NSPro, Phoca and a few other extensions. Not overly loaded with fancy stuff so this was doable.

I found it worked if I did the CP-Transfer for user tables, then the export-import of CB specific tables, then installed CB. I tried once installing CB first and that was definitely not going to work.

Thanks for the feedback.