Seafile CE version 6.1.1 upgrade error

Seafile CE version 6.1.1 upgrade error

The Seafile CE server on Ubuntu 16.04.2 was running version 6.0.9 with no prior issues.

This script would upgrade your seafile server from 6.0 to 6.1
Press [ENTER] to contiune

Updating seafile/seahub database …

[ERROR] Error:
ccnet is using MySQL
seafile is using SQLite3
seahub is using MySQL

Failed to upgrade your database

I have already updated Seafile CE from version 5 successfully many times. Any ideas why this error occurs? I don’t know why SQlite3 is shown as seafile database. We use MySQL for all three databases. I was logged-in as user (not root).