During the last tests of Odoo upgrade to version 16, we diagnosed a serious error - lack of migration of analytical tags.
This is connectes with the new analytical accounting model - the possibility of entering many analytical accounts into one accounting line and resigning from analytical tags. However, Odoo, unfortunately again, forgot about historical data and upgrading to R16 removes all analytic account assignments.
We reported the problem to the Odoo support and after passing (not without a problem) through the first line of support of colleagues from India, the problem was forwarded to the Odoo technical team - we hope for a quick update of the update procedures. The topic is important because many of our clients use analytical tags to describe tax/non-tax costs and revenues (in terms of income tax).
The new analytical accounting model in Odoo is quite interesting and potentially streamlines accountinbg processes. Of course, it requires more thorough tests on databases with more data because the m2m (many-to-many) relationship is not optimally handled by the Odoo ORM.
Update: 20-03-2023
After some discussions with Odoo, we managed to restore the functionality of analytics tags in R16! - however, you can achieve something with Odoo support, after the entry:
We've applied a fix on the AccountAnalytic tag, which was removed in Odoo 16. The list of tags has been saved for each move line. And also filter/group by analytical tags.
Update: 01-04-2023
It's not April Fool's Day, Odoo backtracked from restoring analytics tags in R16 - recommending to stay on R15:
As said previously, we apologize that this change of workflow has caused inconvenience to your business.
We already forwarded your feedback to the Product Owner and it will be taken in account for further releases.
...
Since you are in Odoo 15, I would recommend you to not upgrade to Odoo 16 and wait for Odoo 17 which will have its analytic tags way of working improved.
Once again, we apologize that the changes made in Odoo 16 do not suit you and your business.
We are already working on it to improve it in Odoo 17.
It remains to wait or join the OCA initiative: https://github.com/OCA/account-analytic/issues/551