How to migrate users from 3.71 to 3.93 ?

Hello,

Am trying to migrate all users to the new server with v3.93

Did an export users at server with v3.71 to a file

Then try importing said file at another server with v3.93 but have not been successful.

In our 3.71 environment, we have groups (70 of them) and user population of 1300.

Users can be member of more than one group.

Any advice for above appreciated.

Regards

Jupp