used Environment:

openERP 7.0 

Synology DS716+II

Safari Webbrowser on MBP running on OS X 10.11.5

The following error appeared all of the sudden while trying to print newly created customer bills:

openerp.service.web_services: Exception: tostring() has been removed. Please call tobytes() instead.

more details:

tostring() has been removed. Please call tobytes() instead.

identity=[ImageReader@0x7f7065b9e490]

handle_pageBegin args=()

(<type 'exceptions.Exception'>, Exception('tostring() has been removed. Please call tobytes() instead.\nidentity=[ImageReader@0x7f7065b9e490]\n handle_pageBegin args=()',), <traceback object at 0x7f7065f6b440>)

The issue appeared either after the python update or while setting the billing date in the future, unfortunately I'm not sure exactly when.

Following steps to resolve have done:

1. Dump DB

2. reboot DS

3. Restore DB on a different DS (213+)

4. Restore DB on a Docker VM on DS716+II with newly installed openERP7.0

server.log is available