OPDS broken

[Snoopy]

I just updated the calibre server to the current stable calibre version 2.67 on a Debian Linux Server.
In this Version the OPDS library is broken. The first page works (where you can select the sorting, "from date", "from author"...).
When selecting one of the entrys ("from date" for example) calibre server gives an HTTP 500 Internal Server Error.

This is in server_error_log.txt:

[14/Sep/2016:14:37:34] HTTP Traceback (most recent call last): File "site-packages/cherrypy/_cprequest.py", line 656, in respond
  File "site-packages/cherrypy/lib/encoding.py", line 188, in __call__
  File "site-packages/cherrypy/_cpdispatch.py", line 34, in __call__
  File "site-packages/calibre/library/server/utils.py", line 54, in do
  File "site-packages/calibre/library/server/opds.py", line 488, in opds_navcatalog
  File "site-packages/calibre/library/server/opds.py", line 423, in get_opds_all_books
  File "site-packages/calibre/library/server/opds.py", line 389, in get_opds_acquisition_feed
  File "site-packages/calibre/library/server/opds.py", line 326, in __init__
  File "site-packages/calibre/library/server/opds.py", line 209, in ACQUISITION_ENTRY
UnboundLocalError: local variable 'mi' referenced before assignment