Is it possible to import backup to old jira from newest one

[sha15]

I have tried  to export data from jira  v7.11.1 to old jira v6.4.12

But i get the folowwing error:

You are attempting to import data from JIRA 7.11.1 which is a more recent version than this version. Some features that you may have used before will not be available in this version of JIRA. Click here to acknowledge this error and proceed anyway.

then:

Error importing data: java.lang.RuntimeException: Could not get unique fields for table 'AO_15241E_ADMIN_APIKEY'

We have license limit  10 users  in  new jira. We. need more users, so we need to downgrade  to our old instance v6.4.12 with. unlimited license.

We try to import the data into the old version, or we will think of how to go for a free alternative such as redmine

 1050$ it is too much for 11-12 users.

[Nic Brough -Adaptavist- · Accepted solution]

No.  The data is not backwards compatible, that's why there is an error.

There is no way to downgrade either.

I don't understand why you think you want to do this though.  If you have an unlimited licence and want to merge users in, just upgrade the 6.4 to 7.11, then import the projects.