deploy@production:~$ sudo apt-get -q -y install mysql-client-core-5.6=5.6.19-0ubuntu0.14.04.1
Reading package lists...
Building dependency tree...
Reading state information...
The following packages were automatically installed and are no longer required:
  linux-headers-3.16.0-28 linux-headers-3.16.0-28-generic
  linux-headers-3.16.0-36 linux-headers-3.16.0-36-generic
  linux-image-3.16.0-36-generic linux-image-extra-3.16.0-36-generic
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libaio1
The following packages will be REMOVED:
  mysql-client-core-5.5
The following NEW packages will be installed:
  libaio1 mysql-client-core-5.6
0 upgraded, 2 newly installed, 1 to remove and 17 not upgraded.
Need to get 4,088 kB of archives.
After this operation, 16.2 MB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
  libaio1
E: There are problems and -y was used without --force-yes
deploy@production:~$ sudo apt-get -y install mysql-client-core-5.6=5.6.19-0ubuntu0.14.04.1
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-3.16.0-28 linux-headers-3.16.0-28-generic
  linux-headers-3.16.0-36 linux-headers-3.16.0-36-generic
  linux-image-3.16.0-36-generic linux-image-extra-3.16.0-36-generic
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libaio1
The following packages will be REMOVED:
  mysql-client-core-5.5
The following NEW packages will be installed:
  libaio1 mysql-client-core-5.6
0 upgraded, 2 newly installed, 1 to remove and 17 not upgraded.
Need to get 4,088 kB of archives.
After this operation, 16.2 MB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
  libaio1
E: There are problems and -y was used without --force-yes