The debdiff looks fine however, the version number that you are using for the package in Trusty is incorrect as that same version already exists in Vivid. Instead, if we follow the https://wiki.ubuntu.com/SecurityTeam/UpdatePreparation#Update_the_packaging you'll see that the recommendation is 2.1-4ubuntu0.1. This will be less than the version number in Vivid and is maintainable in that if there is another update to this back in Trusty we can use 2.1-4ubuntu0.2 etc....
The debdiff looks fine however, the version number that you are using for the package in Trusty is incorrect as that same version already exists in Vivid. Instead, if we follow the https:/ /wiki.ubuntu. com/SecurityTea m/UpdatePrepara tion#Update_ the_packaging you'll see that the recommendation is 2.1-4ubuntu0.1. This will be less than the version number in Vivid and is maintainable in that if there is another update to this back in Trusty we can use 2.1-4ubuntu0.2 etc....