This bug was fixed in the package squid3 - 3.5.12-1ubuntu7.1
--------------- squid3 (3.5.12-1ubuntu7.1) xenial; urgency=medium
* Add Breaks on older ufw to fix upgrade path (LP: #1571174).
-- Robie Basak <email address hidden> Thu, 12 May 2016 11:03:06 +0000
This bug was fixed in the package squid3 - 3.5.12-1ubuntu7.1
---------------
squid3 (3.5.12-1ubuntu7.1) xenial; urgency=medium
* Add Breaks on older ufw to fix upgrade path (LP: #1571174).
-- Robie Basak <email address hidden> Thu, 12 May 2016 11:03:06 +0000